>> we have the potential during our lifetime, in the next 10 to 30 years, to slay water and energy shortage, hunger, healthcare, educational issues, where we can create a world of abundance, where we can meet the basic needs of every man, woman and child on this planet. >> woodruff: we examine the clean-up efforts in the gulf of mexico two years after the largest oil spill in u.s. history. >> brown: plus, mark shields and david brooks analyze the week's news. >> woodruff: that's all ahead on tonight's newshour. major funding for the pbs newshour has been provided by: bnsf railway. >> citi. supporting progress for 200 years. at&t the william and flora hewlett foundation, working to solve social and environmental problems at home and around the world. >> and with the ongoing support of these institutions and foundations. and... >> this program was made possible by the corporation for public broadcasting. and by contributions to your pbs station from viewers like you. thank you. >> woodruff: several more secret service careers are ending amid a scandal involving allegations of prostitution and a presidential trip. ray suarez has the story. >> suarez: with new details unfolding all week about just what happened during the president's trip to the summit of the americas, the associated press is reporting the secret service has placed another employee newly implicated in the scandal on leave. officials tell the a.p. that two more agents are resigning today, while another has been fired, bringing to six the secret service employees forced out so far. for secret service agents, it's been a week of disclosures culminating in the news that more will lose their jobs. they were among 11 agents recalled from this hotel in cartagena, colombia, last week on allegations they used prostitutes they met at a local strip club. "the washington post" today identified two of the three agents ousted earlier this week in the scandal. it turned out one of them, david chaney, had posted a picture on facebook of his time protecting republican vice presidential nominee sarah palin in 2008. his comment read: "i was really checking her out, if you know what i mean?" palin had her say on fox news last night. >> well, check this out, bodyguard-- you're fired. the president, for one, he better be wary there of when secret service is accompanying his family on vacation. they may be checking out the first lady. >> suarez: but white house press secretary jay carney said today >> suarez: meanwhile, pentagon officials are looking into allegations that 11 service members were involved as well. and in cartagena, u.s. and colombian authorities continue to investigate the club where the americans allegedly picked up as many as 21 prostitutes. for the latest details we turn to julie pace, a white house reporter with the associated press. she traveled to colombia with mr. obama and has been tracking the developments this week from washington. and is the investigation turning up new details-- details that's pulling in these new people under suspension. >> it appears that there are new details emerging from this investigation. already today we've heard from the secret service, through briefings that they are having with lawmakers and federal officials that the number of secret service employees that are being investigating is up from 11 to 12. we heard from the u.s. military today that the number of people that they're investigating in this is up from 10 to 11. so the scope of the investigation continues to widen. the secret service is continuing to brief lawmakers on the hill. they are briefing the white house. we heard that the president today just received a briefing from director mark sullivan, the director of the secret service. so it appears as more people are being implicated in this investigation, that there are new details that the investigators are learning. >> suarez: careers are ending but some people are leaving on their own steam and some are being fired. what's the difference and why is it important. >> it's a small difference but it is important. the people in the agency who are being fired are being fired because the investigators are finding cause. the people who are resigning are perhaps being implicated to some degree. they may be making a choice that for their careers, perhaps for their family that it's best for them to resign. maybe to try to avoid being fired. but as i said, it is an important difference but it is a small difference. >> suarez: with these latest depar tures that have been reported throughout the day by the ap and others, how many people remain yet to learn their fates? are they fighting their dismissal. and what are they basing that fight on, do we know? >> well, where we stand right now is we had three people on wednesday who were forced out of a job. today we're reporting that there are three additional people who are being forced out of their jobs. and with the disclosure that there are 12 people that the secret service is eingt having that means that there are six others at this point, perhaps more, we don't know, that are still being investigated. it remains unclear whether these people are going to be able to hang on to their jobs or whether we're going to see more fires. >> suarez: susan comings of maine, the senator, has asked openly whether there has to have been previous incidents of this kind. she doubted that this could have been the first time these advance teams ever could have behaved in this manner. can we expect that previous trips are now under the same kind of microscope that the colombian trip was? >> it's certainly possible. because this is raising questions about the president's security. that's really what this all comes down to right now. and that means that there are going to be questions not just about what happened in colombia last weekend, but about what happened when the president has traveled overseas many times previously when he has traveled domestically as well. these agents and officers travel with the president everywhere that he goes. so it's a questions that's being asked at the secret service. it's a question that lawmakers certainly are asking, and that the white house, frankly, is asking and all of us in the press corps obviously as well. >> suarez: what is a jump team, who are they and what do they do? >> so a jump team is one of the teams that goes to the place where the president is going to go ahead of him. some of them travel on a support plane. some of them travel on the plane that actually brings the president's limousine. some of the equipment that travels ahead of the president. so they arrive at the site before the president does. you know, the president arrives in colombia on friday. the incident that we're talking about happened wednesday, thursday. so these agents and officers had been on the ground for some time before the president got there. >> suarez: now with the addition of a new service member in this inquirery as well, let's ask a little bit pore about that. are they in a different line of command. is the inquiry being handled internally by the justice department separately from the one that involves the secret service agents? >> well, right now, everybody seems to be saying the secret service has a process happening. the secret service appears to be having a thorough process. so people want to let this process play out right now. you have a lot of talk about whether congress which does have an oversight roll here may have its own congressional investigation. so far what we have heard is everybody wants to let the secret service have their own investigation. there has been some discussion about mark sullivan, the secret service director, calling for an independent review of this investigation. but right now everything that everyone is focus on is what is happening inside the secret service. >> suarez: any more known about this big party itself. today and through the week it's been mentioned that 20 or 21 women were involved and a similar number of men. what you can tell us about that? >> well, right now we do know from some of the lawmakers that have been briefed on capitol hill that there were about 20 to 21 women who were brought back to the hotel. it is not the hotle that the president stayed at. and there are a lot of rumors, a lot of witness accounts that are coming out of colombia right now, associated press reporters on the ground there have been told that the agents whom we believe to be involved in this incident were drinking heavily. there are reports that they were going out to a bar and partying and bringing people back to the hotel. but right now we're trying to really be cautious about a lot of that detail. you have investigators who are down there trying to dig up that information as well. so we do have some rumors coming out of there but we're trying to be cautious about what we are reporting as this investigation unfolds. >> suarez: but that would be the venue that involved not only secret service agents but the service people as well? >> exactly. they stayed in the exact same hotel. and really, you know, the information that we're getting is very specific at this point to the secret service agents that are involved. the military side of this, we're not hearing a lot of details so far. all we hear from the military is that the now 11 service members that are being investigated were staying at the same hotel, as the secret service officers and that they are being investigated for some type of misconduct so that is where a lot of the unknown questions are right now on the military side of things. >> suarez: julie pace of the associated press, thanks for joining us. >> thank you. >> brown: still to come on the newshour: troubling economic signs, here and abroad; a showcase for cutting edge contraptions; the clean-up of the gulf, two years on; and shields and brooks. but first, the other news of the day. here's hari sreenivasan. >> sreenivasan: a florida judge today set bail at $150,000 for george zimmerman, the man accused of shooting an unarmed teenager, trayvon martin. zimmerman appeared at a hearing in sanford, florida. he apologized to martin's parents, who were sitting in the courtroom, as his lawyer looked on. >> i wanted to say i am sorry for its loss of your son. i did not know how old he was. i thought he was a little bit younger than i am. and i did not know if he was armed or not >> sreenivasan: benjamin crump, the attorney for trayvon martin's parents, said they were disappointed by the judge's decision to grant bail. and, he said, they questioned zimmerman's sincerity. >> zimmerman makes this self-serving apology in court, 50 days later. the real george zimmerman and you all have reviewed it, never once said, i'm sorry. why today. >> sreenivasan: it was unclear when zimmerman will be released from jail. as part of the conditions of his bail, he'll be required to wear an electronic monitoring device and he cannot have any firearms. a commercial airliner crashed in pakistan today, and all 127 people on board were feared dead. the jet went down in bad weather as it tried to land at an airport near the capital, islamabad. as night fell, emergency workers searched the wreckage for any sign of life, but the pakistani defense minister said it was unlikely anyone would survive. u.s. officials have confirmed that four american troops died last night in a helicopter crash in afghanistan. they were in a u.s. army blackhawk that went down in helmand province in bad weather. it was en route to the site of a suicide bombing at an afghan police checkpoint. the presidential candidates in france wrapped up their campaigning today ahead of sunday's first-round election. socialist francois hollande is the current front-runner in the ten-candidate field. incumbent nicolas sarkozy has been hurt by high unemployment, but in nice today, he argued his policies kept things from getting even worse. >> look simply across the borders right next to us, to what has happened to countries whose governments have not wanted to make the choices that needed to be made when they needed to be made. is there one frenchmen who wished for france, the current situation in greece, portugal, spain, ireland, iceland? >> the top >> sreenivasan: the top two vote-getters in sunday's voting will meet in a run-off on may 6. in syria, there was more heavy shelling of the embattled city of homs today, leaving a u.n. cease-fire in tatters. government troops blasted away at two rebel-held neighborhoods in the city. a syrian human rights group based in britain said mortar rounds were landing every five minutes in one area. meanwhile, in damascus and elsewhere, thousands of protesters spilled into the streets once again. they braved gunfire from troops to demand that president bashar assad leave office. huge crowds also gathered in cairo, egypt, to protest against the ruling military. last year, tahrir square was the center of the uprising that ousted president mubarak. today's protests aimed at putting pressure on the country's generals to hand over power to civilians. protesters also called for members of the old regime not to run in the upcoming presidential elections. those are some of the day's major stories. now, back to judy. >> woodruff: as world financial leaders meet in washington, questions loom about the stability of the global economy. on wall street, at least, the mood brightened a bit today. the dow jones industrial average gained 65 points to close at 13,029, although the nasdaq fell seven points to close at 3,000. traders pinned their hopes to strong earnings reports from general electric, mcdonald's, and microsoft. but other, more negative news has raised questions about whether economic growth is slowing again. the unemployment report for march showed the smallest number of new jobs created since november. and this week came data showing housing starts have dropped and factory activity has lessened. at the same time, there are questions about the worldwide recovery. christine lagarde, the head of the international monetary fund, or i.m.f., offered this assessment yesterday in washington. >> we are seeing a light recovery blowing in a spring wind, but we're also seeing some very dark clouds on the horizon. >> woodruff: lagarde said those "dark clouds" include high unemployment, slow growth, and higher gas prices. a day earlier, u.s. treasury secretary timothy geithner sounded somewhat more optimistic. >> i think that if you look ahead, the world is still at the early stage of what's going to be a very long period of pretty substantial rates of growth in the emerging world, the most populous parts of the world. >> woodruff: but europe remains a particular source of concern. the debt crisis weighing on spain, italy, and greece still has the capacity to set back the u.s. recovery. today, ahead of weekend meetings in washington, the i.m.f. announced the 20 leading industrial and emerging nations have pledged $430 billion to help deal with europe's problems. meanwhile, nagging questions about where the u.s. economy is headed are clearly affecting the 2012 presidential race. new polls this week indicate the contest has tightened, with economic worries giving republican mitt romney an opening against president obama. >> he points out he did not cause the recession, but he did make it worse. and he said, "well, look, things are getting better," and i sure hope they're getting better. gosh, i hope they're getting better. but that's not because of him, that's in spite of him. >> woodruff: for his part, the president has charged that republican calls for deregulation and tax cuts will help the wealthy and no one else. >> in this country, prosperity doesn't trickle down. and that's why i'm always confused when we keep having the same argument with folks who don't seem to remember how america was built. >> woodruff: both politicians and the public will be watching critical indicators that may foretell not only where the economy is headed, but who will occupy the white house next year. >> brown: now, mining technology to solve the world's problems. newshour economics correspondent paul solman recently traveled to california and filed this report on some innovative thinkers. it's part of his ongoing reporting, "making sense of financial news." >> reporter: on the back lot at 20th century fox, the world of make-believe, and a typical make-believe vision of the future, courtesy of fox ceo jim gianopulos. >> here's a little peek at what's in store for us. >> at wayland industries, it has long been our goal to create artificial intelligence almost indistinguishable from mankind itself. >> reporter: the sci-fi pipe dream of moving pictures for as long as they've existed. but no dream to those assembled here. this wasn't a film industry gathering, but a conference put together by singularity university, a futuristic silicon valley think tank which fosters and showcases high-tech inventions. their goal is to make the world a better place as fast as possible. co-founder peter diamandis. >> these tools that are now in your hands allow us to really take on any challenge. it's about the most efficient use of capital and tools that have ever existed. >> reporter: singularity's mission is to solve humanity's most pressing problems by spurring new technologies in food, water, energy-- supposedly scarce, but with the tinkerings of technology, says diamandis, potentially abundant. >> we have the potential during our lifetime, in the next 10 to 30 years, to slay water and energy shortage, hunger, healthcare, educational issues, where we can create a world of abundance, where we can meet the basic needs of every man, woman and child on this planet. >> reporter: the key, says diamandis, is that tech growth is not linear-- one, two, three, four, five-- but exponential-- one, two, four, eight, 16, or even faster than that. >> the rate of innovation is a function of the total number of people connected and exchanging ideas. it has gone up as population has gone up. it's gone up as people have concentrated in cities. you know, the coffee shop is the location where people exchange and share ideas. now, the global coffee shop is the internet, and the more people connected, the more innovation we have. think about the fact that a masai warrior in the middle of africa today on one of these cell phones has better mobile com than president reagan did 25 years ago. and if they're on google on a smart phone, they've got better access to knowledge than president clinton did 15 years ago. it's extraordinary! >> reporter: but, says high tech entrepreneur carl bass, we haven't seen anything yet. >> within five to 10 years, we will be printing biological structures with actual function. >> reporter: 3-d printing is already a reality-- copying machines that literally copy in three dimensions toys, product prototypes, and now, living things as well. >> there's some fantastic work going on at wake forest where they're using the same technology of 3-d printing, and they've already printed a human kidney. it's not ready for transplant, but i suspect, within five-ten years, it will be. >> reporter: this conference was filled with sci-fi-like eye- openers. the self-driving car has now been okayed in nevada. >> so we can put your hands right here. >> reporter: doctor dan kraft gave me an e.k.g., and with a stent installed, i've had a lot of them, with his cell phone. >> it's just a two-lead e.k.g., it's pretty basic. but i can see the basic things, that your heart is beating regularly, that your q.r. complex looks normal, that you're not having an s.t. elevation, which is associated with chest pain or acute attack. >> reporter: former astronaut dan barry said the day was soon coming when robots would provide all sorts of services, from the workaday to the intimate. >> robot sex is going to be big, it really is. ( laughter ) it's funny, right? but it's not funny if you're 75 years old and you just lost your partner and you are lonely and by yourself, and still have sexual drive and you have no outlet for that. >> reporter: among the best known inventors at the conference was dean kamen, whose innovations include this prosthetic arm. it freed double amputee chuck hildreth from total dependence; freed his wife from feeding him. >> his wife is standing behind me at the time and starts to cry because she says he hasn't fed himself and she says to me, "dean, you've got a choice-- we keep the arm or you keep chuck." ( laughter ) >> reporter: now, kamen and his cutting-edge contraptions may be familiar, in that we've introduced many here on the newshour over the years, from his medical marvels to transportation aids for overworked newshour correspondents. kamen invented the segway. but for the past decade, his most ambitious project may be the slingshot, a device to make drinkable the world's dirty water. >> it is poison, it is toxic waste. take water that's got fecal matter, cryptosporidium, giardia, every other kind of organic toxin or inorganic. we said, "lets make a box that's small and portable that you can plop down anywhere." >> reporter: a box the size of a dorm-room fridge that almost instantaneously boils and then condenses water, up to 250 gallons a day. >> water that's so pure, it's equivalent to rainwater, it's distilled water. and we believe that if we can build these machines to scale at a cost that is, we think, highly realistic, we will be able to put these things all over the world where people that today have to make a choice between drinking something that will make them sick or possibly kill them and their children, or not drinking at all, which will surely kill them. that's not a choice people should have to make, not in the 21st century. >> reporter: kamen has cajoled coca-cola into distributing these devices. first venue-- rural ghana, where they're now being installed. eventually, slingshots could be everywhere. to peter diamandis, kamen's project exemplifies the mission of singularity university. >> converting that which was scarce to that which is abundant. >> reporter: "abundance" is the title of diamandis' new book, and describes his vision of the future-- transformations in water, food, energy. >> what people don't realize is that we're living on a planet that's bathed with energy. 5,000 times more energy hits the earth's surface than we consume as a species in a year. it's just not accessible yet. but theres good news in this area. there are breakthroughs constantly in solar energy production. last year in 2011, the cost of solar in the world dropped by almost 50%. >> reporter: admittedly, solar now provides less than 1% of u.s. energy needs. but singularity university's other co-founder, ray kurzweil, whom we interviewed by something called teleportec, says the public is pointlessly pessimistic. >> i think the major reason that people are pessimistic is they don't realize that these technologies are growing exponentially. for example, solar energy is doubling every two years. its now only seven doublings for needs, and we have 10,000 times meeting 100% worlds energy needs, and we have 10,000 times more sunlight than we need to do that. >> reporter: okay, one last high tech frontier-- meat. at the moment, livestock production takes up a third of the worlds ice-free land, generates nearly a fifth of the worlds greenhouse gases via organic exhaust, front and rear. and eating just one serving of red meat a day, says a new harvard study, correlates with a 12% increased risk of death. enter in vitro meat, not to be confused with pink slime. >> we have the technology now, it's being done in a number of labs, to actually grow meat products in the laboratory, in the test tube, so to speak. and people say, why, its disgusting! have you ever seen how chicken mcnuggets are made? >> reporter: but an in vitro hamburger doesn't sound like it would be good for you. >> well, actually these kinds of new food products will be far better for you because they'll have the best proteins, the best fats, the nutrients built-in. >> reporter: they'll taste like a hamburger? >> they'll taste better than a hamburger. >> reporter: by this time, we were sufficiently wowed, if not downright overwhelmed. but keeping our journalistic wits about us, we posed the skeptics question --- to vint cerf, known as the father of the internet. did he think this conference might just be over-hyping the future? >> i have been surprised repeatedly by the things that we've been able to do that would have been thought to be science fiction in the past. what craig venter talked about this morning about creating synthetic life, would have been science fiction, and in fact it was science fiction and he's pushed the boundaries of what's real. >> reporter: but what about craig venter himself? the man who cracked the human genome in record time a decade ago is now hard at work creating new life forms for fuels, food and vaccines. he surprised us by issuing a warning of sorts-- singularity's brand new world, he said, is not just around the corner. >> most of what you've heard here so far today is fantasy or bull ( bleep ). >> reporter: venter was venting for effect, perhaps, since he too is creating the future. but think of the worlds growing problems, he says. >> if all these dreams come true, and i hope these people are right, then we will solve everything. nobody has the solutions in hand right now. we have potential solutions. we don't have ways to provide the fuel, we don't have ways to provide the food, clean water, medicine for 7 billion people now. how are we going to do it for 8, 9, 10 billion people in the coming decades? >> reporter: how, indeed? but here in the make-believe world of the future, you can be sure that someone has started working on the question. >> brown: two years on, the gulf still grapples with the impacts of the b.p. spill. these were the sights and sounds of the gulf of mexico in its agony, as four million to five million barrels of oil poured into the sea and spread from louisiana to florida, endangering wildlife and sullying the coastal wetlands. it began two years ago today, when the "deepwater horizon" drilling rig exploded in flames. 11 workers were killed, and the macondo well began gushing crude from the ocean floor. now, b.p. is poised to settle with 100,000 individuals and businesses along the gulf, including 16,000 cleanup workers and coastal residents who submitted medical claims for exposure to oil and chemical dispersants. on wednesday, the oil giant formally presented a federal court with a $7.8 billion settlement, which the court must still approve. the amount includes $600 million in fees for several hundred plaintiffs' lawyers. b.p. is also financing a campaign to lure visitors back to the gulf region. >> come on back to mississippi... florida... louisiana... alabama. >> the gulf's america's getaways spot, no matter where you go. >> come on down and help make 2012 an even better year for tourism on the gulf. >> brown: but the company still faces billions of dollars in potential claims from the u.s. government and the gulf states, as do its drilling partners-- rig-owner transocean and cement supplier halliburton. liability for violating the federal clean water act alone could ring up a $17.6 billion charge. in the meantime, much of the oil appears to be gone, at least, on the water's surface. but questions remain about lingering effects on wildlife. dolphins have been dying in the gulf in elevated numbers, and researchers report fish such as groupers and snappers with open sores and other abnormalities that could be linked to petroleum and other pollutants. so, what is the condition of the gulf today? for that we turn to david valentine, professor of microbiology and geochemistry at the university of california at santa barbara. he's made six research expeditions to the gulf in the past two years. and garret graves, chairman of the coastal protection and restoration authority of louisiana. he's also the state's lead trustee for a collective effort by five gulf states and the federal government to assess the spill's environmental impact. david valentine, i'll start with you, give us an overview, first, of the state of the spill area two years later. >> well, the state of the spill area we know that there is still significant damage that occurred. much of the oil that came out, rough 5 million barrels, much of that went away. it went to the atmosphere. it was degraded by light or degraded by microorganisms. but much of it landed in places like marshes, beaches, the sea floor and the deep ocean. and so there are pockets of damage that are still there. there are areas that are still seeing the impacts, although maybe not as wide spread as had been initially feared. >> brown: garret graves, where do you see the lingering effects? >> with you know, in terms of louisiana we have an excess of 175, nearly 200 miles of our coastal remains oiled, including close to 15 miles of heavily and mod railly oiled shore lines. one of the most frustrating things is the fact that even under the federal government's oil budget report, the last report indicated that you had nearly a billion-- excuse me a million barrels of oil that remain unaccounted for in the gulf of mexico. >> brown: so staying with you, garret graves, what kind of impact does that have along the coast in particular. >> well, we've seen acres and acres, miles and miles of coastal wetlands, we've found thousands of birds. we've recently seen hundreds of dolphins an other mammals that have been impacted. so we're seeing a number of impacts in specific areas. >> brown: david valentine, pick up on the question of the dolphins, the question of fish that i raised in our settup, this potential abnormallallities. how much is really known about the cause. >> right now not a lot. the issue that we're facing is that we are now looking very carefully at the state of the ecosystems in the gulf. and we're seeing a lot of problems and these ray couple of examples. deep-sea coral would be another exam. the problem is we didn't have baseline information to tell us what the condition was like beforehand so the problem that we are currently facing we're going to face for some time is to pick apart the, these issues and figure out how much of this is really caused by the deepwater horizon, how much is because interested other issues, be it other oil exploration, activities or just other things that are happening in the gulf. so we have to make the link. and that's where things stand right now. >> how does that work go on. what kind of research does that entail? >> well, it's research that has to be specific to the questions that are being raised. and so in this case, you know, we're talking about a number of different things. each one has to be looked at individually. you know what are the real incidents, how do they relate to the oil, and then studies have to be designed to go out and look very carefully at the cause of the factors, trying to isolate them. it's difficult. it's doable in some cases. but very difficult. especially if there didn't happen to be existing data from before the spill. >> brown: well so garret graves, where do questions like that leave folks in louisiana, especially either making a living or living, period, along the coast. what kind of questions are still out there? >> well, you know, when you start seeing these anomalies like the dolphins, like the corral, and many of the other assessments that have come out that you mentioned earlier, the grouper and the snapper, and some of the legions that have been-- legses that have been reported on those fish, you begin seeing these anomalies and start trying to put that picture together on what the overall health of the gulf is. at this point we don't know. after some of the other oil spills it's taken five or ten years to accurately quantify what has happened with the gulf of mexico. what we're doing to help the fisherman is that we are testing the seafood. we are testing every piece of consumable seafood, the most tested seafood in the world to make sure that it doesn't cross the threshold of safety for consumption that the fda has set. >> brown: now david valentine, one of the questions we all looked at a couple of years ago was the dispersants question. what is known at this point about lingering impacts from that? the use of dispersants? >> well, you know, the dispersants were applied initially in two very different sorts of ways. one was a dispersant application at the surface, something just over a million gallons of it. and this was to prevent rafted oilslicks at the surface from making it ashore and hitting beaches harder than they already were hit. the other form that the dispersant was applied in was at that ruptured well head it was sprayed directly in, about 770,000 gallons of it. and those were made for very different reasons. the at the wellhead it was being added in order to prevent the health problems and the workers above. and anecdotally we still don't know if that was really the right decision or not it was made at the time based on people's observations that it made conditions better. now two years later we still don't have a lot of answers. we know that we made those decisions. we know why we made them. we know where much of that dispersant went and we were able to show that the stuff added in the deep stayed in the deep. but we don't know what the effects were. and that's going to be a very difficult issue to pick apart. and it's going to require substantial amount of study over time. >> brown: garret graves, what is the state of the coordination of looking into all of these things. are you represent your state, are you part of this coalition of, in the region. who is doing what at this point and how much cooperation is there and is it still working with bp at this point? how does it all work? >> well, the states and two federal agencies, the fifl five gulf states and federal agencies have a group representatives from the states and department of interior and commerce that are collectively working together. we have literally hundreds of different assessments that are under way. we've taken thousands of samples across the gulf in various forms to try to begin painting that picture of the gulf, and the gulf's health and the gulf's productivity. as noted, we have seen some anomalies. we've seen anomalies in different areas and trying to draw conclusions to help understand what exactly is going on with the overall productivity and overall health of the gulf. while the seafood we've tested so far has been safe, we are trying to work to determine the productivity levels of the gulf to ensure that the shrimp production, the oyster production, the fin fish production come back up to the levels that were in place prior to the spill, to ensure that the fishermen, to ensure that the restaurants all have a bright future in the gulf. one of the challenges is, is that if you look at an example of valdez it took nearly four years after the spill to see the herring supply collapse, that was unanticipated. we have to be careful to not draw premature conclusions, to not close the book on this too early. in terms of graying the-- grading the overall health of the gulf this is a very thorough process and we are he working toward an accurate assessment process to be sure we know exactly what happened as a result of it this spill. >> brown: briefly david valentine, it's an awful way to learn things, but can anything be said about what scientists have learned from this experience at this point? >> yeah, i think this was in many ways a forbidden experiment. something that scientist was never think to do. but that industry in this case did for us. and i don't want to call it a bright spot but we've certainly been able to learn a lot about how nature works. and we've really been able to focus also on how the gulf of mexico operates as a system because of the attention that has been given to this area and the resources that have now come into looking at ecological issues here. >> brown: all right, david valentine and garret graves, thanks so much. >> thank you. >> thank you very much. >> woodruff: and to the analysis a short time ago the agency announced three more employees have resigned and one additional has been implicated. another was cleared of serious misconduct but will face administrative action. and to the analysis of shields and brooks-- syndicated columnist mark shields and "new york times" columnist david brooks. gentlemen, welcome. >> thank you, judy. >> woodruff: different subject, david, flurry of new polls this week in the presidential election. what did you take away from what you saw? it showed all of them virtually show the race is tightening. >> a little obama edge. why don't i give you my mehta theory of where we are going to go in this election. usually there is a dominant majority, the democrats in the 30ss, republicans in the 80s. in my view we have two minority parties. we have two parties that have a minority of voters, in what they call a moon party, sort of two moon parties. and then the electorate swings volatilely between whatever party they hate least at that moment. so i think we are at a moment of pretty strong volatility in the electorate. and so we enter the race with both parties with a reasonably fervent 43% and a lot of people are disgusted with both so when you enter the race when you look at the polls, obama may be ahead, he may be slightly behind, they may be tied but i think will be more volatile than the last couple presidential elections because of the extreme alienation of the electorate. >> woodruff: do you see that kind of volatility. >> the moon sun. >> woodruff: galaxy. >> i see a star, judy. no, i think it's a lot more like 2000 and 2004 elections which were both close, both fiercely fought, right now, than it was like 2008 where theres with a breakout winner in president obama. i think right now we've got the no clear favorite. the president is better off than he was six months ago. sense of the improvement in the economy. but and he is far better on all the personal qualities. he cares about people like me, more likable, more approachable than his governor r078 romney. but it's an election about the economy. and when the economy is bad, the economy is the only issue and that's the one place where mitt romney has an edge in "the wall street journal"/nbc poll that came out today and the other surveys as well. >> woodruff: a few weeks ago was showing the president had a little bit more of a lead than he has now. so is that the economy, does that explain -- >> well, i think what ef's got, republicans have consolidated. i mean after a rather bitter primary in many respects, they have all come home to mitt romney right now. so i think that ups his numbers, his own numbers have improved. my theory is a little bit different about the two parties. i think that the democrats when they pick a presidential nominee, they basically have to fall in love. they like somebody who is an underdog, unknown and running for the first time. witness jimmy carter. witness george mcgovern, barack obama, bill clinton. republicans by contrast fall in line. and you can see that, they like somebody who has the endorsement of party leaders, who leads in the polls and basically has run before. ronald reagan, george herbert walker bush, bob dole and mitt romney and john mccain. so republicans have i think come together more quickly. the one thing republicans have going for them that the democrats had going for them in 2008, there is more enthusiasm among republicans by about a 10 point margin over democrats right now. that's the reverse, almost the reverse of where it was four years ago when president obama won. >> woodruff: so david, what do you look for in the months to come. we talked about the economy. we talked about the level of enthusiasm. what do you-- dow look at everything. >> yeah, a couple things have to be decided by the candidates. as mark mentioned in the polls especially "the wall street journal" nbc poll, romney has a slight edge on who you can handle the economy but huge deficits on can relate to people like you on the personal stuff so does romney try to build that up. i guess he does but i guess he is not going to win a popularity contest, an elegance contest with barack obama. so what he has to do is say it's not about me, first of all it is about obama but i will offer you these four things i will deliver as president. and he really hasn't told the story of what the next four years will look like. so we can't just say i'm a businessman, trust me, i know how to run a business. i think he says i'm going do a, b, c and d, you may not like me but hire me to do these things and i will do them for you. i think that's really the gap he has to fill. and the obama people have to decide if they are didding to attack romney as an extremist or flip florp. you can't do both. and so they have to make that decision. these days they seem to be heading in the extremist direction which i think is the wrong direction. >> woodruff: is that right, because the reporting you are seeing now or the analysis is that they were focusing on mitt romney the flip-flopper. now it's mitt romney extreme. >> and i think that is a, less true. and just not going to sell with people once they see romney in the general election campaign. >> woodruff: what do you think? >> well, i don't know which tactic the obama campaign will eventually move to. i think the, by calling him an extremist, i mean what you can certainly do from several positions he's taken, the man who calls for a 20% tax cut for everybody, right now, as he is talking about fiscal responsibility, which would lower the top rate to considerably where it was below when ronald reagan was president in the really festival days of the rep kaj-- republican resurgence. but where he is on immigration where he moved on immigration, praising arizona and all the rest, i think he's vulnerable because he can't change. es an in a very difficult. he can't flip, he can't flop. i mean because that is, that is the rubric of republicans right now. and it's a great misgiving about republicans, that they have for him. is whether in fact what does he believe. who is mitt romney. >> woodruff: so are you saying maybe the extreme conservative line may be -- >> i think that if you tie him, judy, i mean by his positions to values, in other words, he doesn't care about the middle class because he endorsed its ryan budget plan. i mean i think that's-- i'm not endorsing it, but i think it's a logical campaign approach. i think what we have, you asked what the campaign is about, right now i'm pessimistic about this campaign. i mean i don't see us coming out of this campaign, given the current status of both carn datas and their positions, with any kind of an improved feeling about the country, where we are going. >> woodruff: pessimistic as a citizen. >> exactly. i don't see a sense that there is going to be an endorsement for obama's position or whatever his second term is going to be like. or for romney's. >> i've got a little more optimistic about it. not that you see it yet, but it in embryo form. they are heading toward a big debate. they really do have different views of what brought us here. obama says we've had the business resurgence, deregulation, it lead to a crackup and now i'm trying to put the pieces together in a balanced way. romney says we have had decades of really growing federal will vie than, stagnated economy that is two different visions. they haven't yet told the story of where those vision goes. but that is a pretty fundamental debate. and we could in theory, if we drag them that way, could have a debate where they confront what those two big visions mean. it's equally likely of course that the super pacs and trivialities will distract them away from those big visions. and the reason the candidates want to get away is because when you talk about what is going to happen in the next four years it is probably pretty nasty choices. health care spending, budgets, tax. and they would rather not talk about that. >> woodruff: mark, you were a part of, you sat in on and watched the democratic poster peter hart put together, i guess a group of 12 voters, republican voters down in north carolina this week. >> florida. >> woodruff: sorry, florida. looking at i guess its goal cass to look at what did mitt romney need to do. tell us what due -- >> these were republican voters and they voted for john mccain, marco rubio, or rick scott the governor of florida. and they were basically romney, although they hadn't all been for romney in the primary. and but what was amazing, judy, is they have no idea who mitt romney is. and part of it you could see it, romney's strategy in the primaries was to disqualify rick perry, to disqualify newt gingrich, to disqualify rick san tore tomb. he made the case on why they should not be president. he's never made the case on why he should be president. and that comes through. i mean people say look he's not a regular guy. i don't feel-- he fails the would you like to have a beer test, completely. barack obama is seen as far more approachable and regular, and natural than even in these republican voters. they don't know we are stands, what he really believes. they admire the fact that he he's a good husband, good father, good values and has been a success in business. but there isn't any personal or philosophical connection with him. >> woodruff: what do we take away from an assessment like that, david, at this stage in its campaign where you still have seven months to go. he's got time. >> on the other hand he has been running for president for five years. so to me the difficulty he faces and i think will just have to overleap this hurdle. he doesn't want to take on more mojism, he doesn't want to talk about the two things that i think are core to his life, his faith and his family. and i think you just have to leap that over and say i'm going talk about my family. i will talk about where we have been from, what we have been through over the generations, being beaten back to pov the and building it up. i think that is who he is. >> woodruff: his ancestors. >> but include his dad's family and his own family. it's a pattern. >> it is an interesting thing, two or three of the voters mentioned their concerns and doubt about his mormonism. and what influence it would have upon-- and these were people supporting romney. so i think it's imperative that he have a houston minister's speech moment where he does address it, how the values that have animated him or have defined him and to make mormonism more american mainstream in its values that are comparable with american values. >> woodruff: and again these are republican voters. >> these are republican voters that were interviewed. >> woodruff: both campaigns finally rolled out a big initiative effort this week, david to appeal to latino voters. where does that stand? >> i actually think ot bama administration did a reasonably good job on this. the tendency is to go speak spanish and do ethnic cliches that you pileup. one of the things they did intelligently was just do it straight policy and they emphasized pell grants and other college scholarships. they said here's 9 policies. you know, some of are you middle class, lower middle class, whatever. here are policies that have helped you. and that's probably the right way to do it. i'm not a huge fan of breaking the electorate up into nichee or latino voter ace big niche because latino varieties them ef-- themselves are a diverse population. just tell your story and if it works it will work with white, latino, black voters, they told just a version of their story but in spanish. >> it's a good point. i would add this. judy, half the growth in the country between 2000 and 2010 were latinos, if you had, if voters had voted the same proportion demographically in 2008 they did in 1984, john mccain would have beaten barack obama. the country has changed that much to the point where we are looking at an election where maybe 71, 72% of the electorate is white. which is a drop much better than 15% over a generation. so republicans don't have, i mean, you can't get enough white votes to win by themselves. and republicans have to come up. this is where romney is in a terrible dilemma because he moved so hard on immigration and what the theme of anti-latino in the primaries. and you know, i think he is trailing by 69 to 29 in "the wall street journal" nbc poll among latinos so it is a real problem. >> woodruff: it's not a problem having the two of you. mark shields, david brooks. thank you both. >> brown: finally, tonight's edition of "need to know" examines the death of a mexican man who tried to cross the border illegally near san diego in 2010. his beating by u.s. border patrol agents was recorded by two eyewitnesses. tonight's report is the result of a joint investigation by "need to know" and the investigative fund of the nation institute. the correspondent is john larson. here's an excerpt. a warning-- it contains some violent images. >> across san diego this is 10 news at 5. >> human rights advocate called it a brutal beating. >> sans diag police are investigating the death. >> in early june 2010 residents of san diego awoke to reports of an incident at the border with mexico. according to san diego police, an illegal immigrant caught sneaking into the country basically violent when border agents removed his handcuffs. but it's what happened next that was reason for a police press release. due to the combative behavior of the immigrant, read the statement, u.s. border agents used atationer to-- taser to subdue him and the subject stopped breathing. >> the subject 342-year-old anastasio hernandez rojas lived long enough for his family to see he had been beaten and bruised. by the time he died, his family believed he had been killed by u.s. customs and border protection agents in an excessive use of force. >> they didn't stop to think about the fact that he had a family. that he was leaving five kids and a wife. >> reporter: the san diego medical examiner ruled the death a homicide listing the cause of death as a heart attack due to the altercation with law enforcement. but the coroner also found methamphetamines in his blood which raised the question, had methamphetamines somehow contributed to the violence? whatever happened, the story lasted just a few days and mostly receded from public view. until now. >> pore far. >> reporter: what u.s. border agents did not realize is that eye witness videos of the incident caught the sounds of hernandez rojas screaming and pleading for his life. >> no. >> reporter: and now a never before seen eye witness video of the incident raises new disturbing questions. the dark video reveals more than a dozen u.s. border agents standing over hernandez rojas. >> hey, no! >> it shows the firing of the taser. >> was hernandez rojas as the police press release suggested combative when he was killed? or was he on the ground handcuffed. bd >> brown: "need to know" asked for interviews with u.s. customs and border protection, the department of homeland security, and the justice department. all declined. "crossing the line at the border" airs tonight on most pbs stations. in several markets, including washington, boston, san francisco, and iowa, it's on earlier than usual. next week, the newshour will have several reports on immigration as the supreme court weighs arizona's tough new law. >> woodruff: again, the major developments of the day: three more secret service members resigned amid a prostitution scandal. the agency also reported a 12th employee has been implicated. and a florida judge set bail at $150,000 for george zimmerman in the killing of trayvon martin. mark and david keep up the conversation online tonight. hari sreenivasan explains. hari. >> sreenivasan: on the "doubleheader," they talk politics and sports, including thoughts on fenway park's 100th anniversary. find that on our "politics" page later tonight. plus, we continue our reporting from pakistan with the story of the death this week of a senior newspaper editor. that and other reports from pakistan are on our "world" page. all that and more is on our web site, newshour.pbs.org. judy. >> woodruff: and that's the newshour for tonight. on monday, we'll report from pennsylvania on the challenge mitt romney faces winning over social conservatives. i'm judy woodruff. >> brown: and i'm jeffrey brown. 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