Obsession with secrecy. All that and more on tonights pbs newshour. Major funding for the pbs newshour has been provided by bnsf. And with the ongoing support of these institutions this program was made possible by the corporation for public broadcasting. And by contributions to your pbs station from viewers like you. Thank you. The pentagon reported the incident today in a video briefing. Russian air strikes have been hammering targets across syria. A u. S. Military Spokesman Says the Close Encounter underscores the risk. I mean, its dangerous if two sets of aircraft come into the same piece of airspace without very clear, laidout protocols for safety of all involved, which is why we have sat down with the russians to establish some safety protocols. Woodruff meanwhile, at a moscow event, president Vladimir Putin blamed washington for a lack of coordination on the competing air campaigns. translated we asked the u. S. On the military level to give us the targets which they consider to be the terrorist ones for sure, 100 . But the answer was no, we are not ready to do that. Then we thought and asked another question then could you tell us where we should not hit . again, no answer. So, what should we do . woodruff the next round of talks between the u. S. And russia militaries will be tomorrow. Meanwhile, the Islamic State called today for muslims to launch a holy war against both countries. The appeal was in an audio message posted online. In afghanistan, the taliban announced its pulling back from kunduz, in the north, to avoid further civilian casualties. Taliban fighters held kunduz for three days last month, and the fierce fighting forced thousands of people to flee. Now, fighting has shifted south to ghazni, a city that lies along the main highway between kabul and kandahar. Irans parliament voted today to approve a nuclear deal with the u. S. And other world powers. It came after rowdy debate and objections from hardliners who argued the deal concedes too much to the west. Now, the bill goes to the Guardian Council of 12 clerics, for ratification. The stance of Supreme LeaderAyatollah Ali Khamenei is still unknown. He has the final say on all matters of state. The worlds top two beer makers are joining forces. Anheuser buschinbev sealed a deal today to buy s. A. B. Miller for 106 billion. In a company video, the head of a. B. Inbev said its all about consumer choice. And local brands would provide more choices for beer drinkers in new and existing markets around the world. Consumers would have more opportunities to taste a wide range of beers, ranging from specialty and craft beers to local champions and Global Flagship brands. Woodruff the new company will control about a third of the global beer market. But the sheer size of the deal could run into resistance from regulators, especially in the u. S. And china. And, wall street had a down day after china reported its imports fell 20 last month, over a year ago. The Dow Jones Industrial average lost 50 points to close back near 17,080. The nasdaq fell 42 points and the s p 500 dropped 13. Still to come on the newshour digging into the evidence of what shot down the malaysian passenger plane over ukraine. How a possible joe biden run could influence tonights democratic debate. A new book reveals untold dimensions of president nixons white house. And much more. A 15monthlong investigation into what brought down Malaysian Airlines flight 17 last year is over. And as most expected, it concluded a missile targeted the plane. The airliner was traveling from amsterdam to kuala lumpur, when it was struck over eastern ukraine. No one has taken responsibility, but todays report set sharpened suspicions, and denials. Reporter like a giant jigsaw puzzle, the piecedtogether wreckage of the planes front fuselage loomed over the chairman of the dutch safety board, as he announced the findings flight mh17 crashed as a result of the detonation of a warhead outside the airplane, above the lefthand side of the cockpit. Woodruff in short, as this dutch animation depicts, a russianbuilt missile, identified by shrapnel and paint, blew the malaysian airliner apart on july 17th last year. The report says the missile exploded less than a meter from the cockpit, spraying metal fragments into the plane. All 298 people on board were killed, as wreckage, luggage and bodies rained down over eastern ukraine. Investigators say some passengers might have stayed alive for a minute or so after impact, but were too dazed by shock, cold and loss of oxygen to know what was happening. Barry sweeneys son was one of those who died. Because of the impact of the missile, the explosion, the confusion and everything else, it sounds that everybody died peacefully. And thats comforting me, and i would think, all other families of flight mh17. Woodruff the investigation also plotted simulated flight paths and concluded the missile was launched from a 124square mile region. Russianbacked separatists controlled that area, but the report does not address who fired the weapon. Still, the russian state arms producer that makes the buk missile disputed those findings. It said its own experiments prove a much older missile took down the plane. translated the general engineer of missile 9m38 decided that the safety period for using this missile including all extensions is 25 years. Use of these missiles was prohibited after that, and they were retired from the russian army. Woodruff the arms manufactuer said that kind of missile is still used by ukraines military and that, in fact, it was launched from ukrainiancontrolled territory. Either way, the dutch investigators said today the plane never should have been in that air space to begin with. Ukraines position is that there was insufficient reason for closing the airspace above the eastern part of the country. We have, however, concluded that, as a precaution, there was sufficient reason for ukraine authorities to close the airspace above the eastern part of their country. Woodruff ukraines foreign minister took issue with that conclusion, speaking today in we look at some of the details of todays findings with a long time investigator. Peter goelz is a former managing director of the National Transportation safety board. He oversaw the investigation of t. W. A. Flight 800 that crashed off long island 20 years ago and speculation then of whether a missile brought it down. Peter goelz, welcome back to the program. How good a job did this International Team do, do you think, of piecing together what caused this crash . I think they did an extraordinary job. I read the report late last night and this morning. Its almost 300 pages in length. It is detailed. It is factual. And its very sober. Woodruff so among other things im struck by how it describes pieces of shrapnel from this missile, paint from the missile embedded in the bodies of the crew and people who were sitting in the front of the plane. Does it leave any doubt of the kind of missile that hit right at what they said, a meeter from the plane . Theres no doubt about the type of missile or where it struck. When a missile detonates in that proximity to the aircraft, it leaves very distinctive marks, as you can see on the nose of the aircraft. These holes, these hundreds of holes, they have microscopic bits of the metal, of the piece of shrapnel sometimes in the hole. And you can trace it back to the source. Woodruff and we heard the dutch investigator call it the 9n314m missile. What does it tell you, adrian peterson, what does it tell you, peter goelz, that is a missile that blew up just outside the plane . It didnt hit the plane. It blew up before it hit the plane . More recent missiles have proximity fuses. They are driven by radar. It sense when theyre in close proximity to the far get and they explode and disperse a shrapnel in a very defined way. We did tests in 1997 at the china lake Missile Center in which the u. S. Detonated warheads near pieces of aircraft skin, the metal, the aluminum. We saw the very distinctive patterns that they left. So the investigators knew what they were looking for and knew what they had when they found it. Woodruff it is possible to say one side or another would have had this kind of missile . We know the russians are saying, new york we dont have this missile in our arsenal anymore. The ukrainians were using this. I think investigators that ive spoken to who were involved in this timeconsuming effort have indicated that there is other Information Available from intelligence sources that indicate where this missile was launched from, and that its very clear that it was well inside the separatist territory. Woodruff so is it possible, do you think it will eventually be possible to say this was the source, this is who fired that missile . Yes, i think the truth comes out. After kaloo7 was shot down off the soviet union, it took years, and it took years of activism on the part of family members, but eventually the russians admitted what happened. I think it will take time, but the truth will come out in this case, as well. Woodruff and one other thing, the discussion today about whether this passenger plane should have been flying over an area of conflict. That is probably the most important recommendation that the dutch made. You know, that day there had been almost 150 aircraft traveling along that airway, the same one that malaysia. Woodruff passenger planes. Thats right. These were passengers planes. They said there was very poor coordination between the Civil Aviation authorities and the government, and the governments at play, and they probably shouldnt have been there in that area of conflict because planes at lower altitudes, mind you, had been shot down. Greater attention has to be paid to the safety of the airways. Woodruff peter goelz, thank you very much. Thank you. Woodruff we will hear a great deal from the five democrats vying to be president tonight as they take to the debate stage for the first time in this campaign. But hovering over them are questions about a potential sixth candidate Vice President joe biden. Some democrats are getting impatient and say its time for him to decide whether or not hes going to run. The newshours political director Lisa Desjardins reports from las vegas on the biden factor. Reporter the man not on stage tonight im joe biden. Reporter has had plenty to stay this month. Going off script at an hispanic heritage event, he took aim at donald trump and the republicans on immigration. Mr. Trump and the stuff youre hearing on the other team, and this isnt about democrats and republicans, its about a sick message. Reporter with Union Workers on labor day, he went after tax breaks for the rich. Why in gods name should man or woman making 50,000 a year pay at a higher rate than someone who makes tens of millions of dollars on wall street . Reporter and at a solar convention, it was climate. Make no mistake about it, folks, Climate Change is caused by human endeavors, and its an existential threat. Whats at stake is whether we have a future at all. Reporter the topics are from man on pause. Biden has been mourning the death of his son. He told the late show and Stephen Colbert hes not sure if he has the heart to run for the white house again. Id be lying if i said i knew i was. There. Reporter as biden carefully consideration whether to enter the race, democratic voters and funders focus on the debate stage here in las vegas tonight and the declared candidates, and some political experts say bidens window to jump in the race may be phi mite. He doesnt have a long time. But hes got several weeks more. Reporter hillary rosen, a democratic strategist. There are some filing deadlines coming up next month that he has to deal with. But were going to have a debate a month for the next six months. We have to get in. Reporter what would it mean if biden gets in . Heres a look at how those on stage tonight did in the latest national nbc wall street journal poll without biden. Its a race between clinton and sanders, but hypothetically, beam biden into the mix, and he would get nearly one in five democratic votes, taking some from sanders, but the biggest chunk would come from camp clinton. At the same time, clinton faces dropping favorability ratings, meaning a debate without biden is a key opportunity for her. If hillary does really, really well and democrats end up rallying around her, you know, that might take some of the air out of the biden balloon. And so theres a lot of pressure on hillary. Things can change in a heartbeat. Reporter adding to the pressure is the super pac draft biden. Six weeks after the election, my hole life was altered forever. Reporter they ran an ad stressing how biden coped with the stress of the loss of his wife, daughter and now son. Biden asked the group not to run the ad. Its part of the mood around biden right now, but that could change. Primary voters love what they cant have. Theres always the what if. What if this person were to run or this person were to run . I think youre getting that right now with Vice President biden. I think its a lot different once you become a declared candidate. Reporter look at bidens work on the 1994 crime bill, no criticized for propelling overincarceration. In addition, biden supported the transpacific trade deal, unpopular with democrats and opposed by clinton and sanders. And with 36 years in the senate, biden is an insider in the year of the outsider. The Vice President has indicated it all comes down to a personal decision, but some think tonights debate might matter. Should Vice President biden or his consultants see a debate where none of the candidates are truly resonating with the voters or the audience, that might be something that factors into his decision as to whether or not he runs. Woodruff and lisa joins us now with the latest from the wynn hotel in las vegas, the site of tonights debate. Lisa, welcome. So Vice President biden is not there. Youve been talking to a lot of people. What are they saying about the two frontrunners and what they need to do tonight . What is their strategy, Hillary Clinton and Bernie Sanders . I think thats right. Most people are looking for that matchup tonight in particular. Lets start with. Bernie sanders. I just talked to him campaign spokeswoman, simone sanders, no relation. She says he will not go on the attack. But they are saying he will give differentiate himself from health care. Expect him to talk about trade, and that will come back to that interview that you had with Hillary Clinton in which he announces she opposes the transunion partnership. Bernie sanders talks about his consistency. This is a relatively new position for Hillary Clinton. Hillary clinton is saying her campaign wants her to stay on message but also stay positive, but same thing, expect her to differentiate herself, especially on the issue of guns. We can talk about the debate stage, but the truth is, judy, the fight between these two democrats has already started in las vegas over unions. Here you see Hillary Clinton yesterday speaking at a protest of culinary workers. That is the Largest Union in nevada, and its a group that has not endorsed yet. They endorsed barack obama in 2008. Hillary clinton certainly wants them this time, and she showed that yesterday. It is a very tense fight over unions. Expect a lot of talk about workers tonight in the debate. Woodruff of course being a huge part of the democratic base, the labor unions. Will lets talk about some of the other candidates on the stage. We havent heard a great deal, lisa, about the former governor of maryland, martin omalley. Hes been trying to get his voice heard. But its been tough in this campaign. What are we looking for from him . Thats right. He may be the one with the most at stake tonight, judy. Martin omalley in some polls is under 1 , just barely above 0. Thats something i dont think anyone expected a few months ago. He has a lengthy resume. Hes personable. Hes a good campaigner, but he hasnt taken hold. Judy, tonight we expect if anyone goes on the attack, it will be martin omalley. He will try the look as though hi is more of a progressive than health care. As i say, the stakes are very high, judy, so high, in fact, if he doesnt improve in the polling, judy, he may not make future debates because of a 1 or higher cutoff established by different networks. Woodruff lisa, the other two on the staining are candidates we hear even less about. Thats the former senator from virginia, jim webb, and the former senator and governor of the state of rhode island, lincoln chafee. What are their campaigns saying about what they need to do tonight . Right. Both of them are stressing the homespun nature of their campaigns. Part of that is they are more lowfunded campaigns. They say theyre proud of that. For example, with jim webb, talking to his folks, we know that those who will be speaking for mr. Web here in the spin room are just friends of his, some of them friends of his through the military and his experience there, but people who have never been in a spin room before. I think those two men in a way have nothing to lose, and so we should expect to see if one of them has an unexpectedly strong moment tonight. I think one thing overall for all of these candidates is this debate is especially important because its the first in a long season, and if our viewers will remember new york 2008, by this point, there were already 13 debates. Can you imagine . Its sort of hard to understand, but this being the first at the start of the cycle, its very important. Woodruff just very quickly, lisa, difference between a Republican Debate and a democratic debate . You covered both of them now. What does it look like . What does it feel like . It is a vast difference, judy. I think tonight we think because thre are fewer candidates, and to be honest, because their disagreements are a birth more nuanced, we think we might have a more serious policy debate. A lot of us love those, and hopefully well get one tonight. Well see. Woodruff lisa desjardines, our political