the children, when mom is on the front lines. "nightly news" begins now. captions paid for by nbc-universal television good evening. this was a dark day for the nation's finances and for millions of americans with a financial stake in the markets. the very same americans who are still processing the fact that our country has lost its top credit rating. here's the damage from today. the dow down over 634 points. that's the sixth largest point drop in its history. the worst since '08. nasdaq lost just about 7% of its total value. s&p 500 lost 6.6% of its value in one day. the president went on television at midday to reassure americans but the damage was done. the markets continued to drop while he spoke and the damage continues. it is a bigger systemic problem with no real end in sight. we begin our coverage tonight with cnbc's maria bartiromo. she's at the new york stock exchange. maria, you won't see many days like this one in your lifetime. >> reporter: it is true, brian. what a day today on wall street after last week's sell-off and the credit downgrade by standard & poor's late friday. anxieties mounted over the weekend and all eyes were on wall street this morning. stocks dropped right at the opening bell on wall street as the selling that started thursday just kept going. not a single stock on the s&p 500 ended in positive territory. >> that's really bringing the market into the red. >> there is concern that the s&p downgrade may do something to consumer confidence and thereby ease us a little closer to the infamous double dip that everybody is worried about. >> good afternoon, everybody. >> reporter: president obama came out to reassure investors. >> this is the united states of america. no matter what some agency may say, we always have been and always will be a aaa country. >> reporter: while the markets sold off another 400 points after the president's speech, sales of u.s. treasuries remain strong, easing fears that interest rates might rise on mortgages, cars and student loan >> if the world say risky place and investors shed risk, they're not going to shed the least risky asset, still u.s. treasury securities. >> reporter: in an attempt to avoid a recession in europe, the european central bank bought bonds to keep spain and italy afloat but that may not be enough. >> there is going to be a bigger burden on france and germany. the question is, do they have enough money -- do they have the will to bail out the other countries? >> reporter: some investors sought safety in gold, sending gold prices up more than $61 to a new record high while oil closed just above $81 a barrel. >> look around. the compass is spinning. investors are being turned off. >> reporter: despite the chaos, dan arbis sees one possible advantage to the downgrade. >> some day we will thank the s&p for the downgrade. it is a message to washington, we must begin to address the long-term solvency of the united states of america. >> reporter: next big event to watch, the federal reserve will meet tomorrow in its regularly scheduled meeting and investors will be paying close attention to see if the fed says anything about the economy and whether it requires additional stimulus right now, brian. >> maria bartiromo starting us off from the floor of the exchange. maria, thanks. let's go over to cnbc's global headquarters, david faber is there for us tonight. let's pick up on the point the last gentleman made, i'm not a historian, but i think this is a leadership moment potentially for the president of the united states. he's getting pressure to force congress into a sudden breakout of sanity. if that happens, how long until we could get our top credit rating back? >> it could still be some time until at least s&p comes back. these are long-term problems. they aren't solved overnight. yet that certainly would be a positive. i think you saw the president today trying to engender confidence in the press conference because confidence as we have seen over the last couple of weeks has come in short supply given the debate over the debt ceiling, the downgrade by s&p and, of course, days like this when the market, all which of can become a self-fulfilling prophecy, you simply don't want to do much in terms of making an investment if you're a consumer or a ceo. >> what happened to bank of america today? they had a very bad day. i read somewhere 20% down on the day. >> reporter: that's right, the stock of the company lost 20% of its value in one day. kind of shocking and frankly quite scary. bank america is a reflection of the american economy. because of the slowdown in the economy, it is suffering. it is also the mortgage mess. the foreclosure crisis and also the packaging of securities that have been made and sold made up of mortgages that it is now in a position of buying back. add in turmoil in europe, you get all the banks down. bank of america really suffered today, brian. >> david faber, after what we know was a long day for all our on air colleagues over at cnbc, thank you, as always, for being with us. and a quick program note for our viewers, again tonight, cnbc will have special coverage of the markets this evening beginning at 8:00 eastern time. this has been a tough couple of days, in addition to the economy and the markets, we got word over the weekend that america had lost 30 service members including 22 navy s.e.a.l.s in afghanistan when their chinook dual rotor helicopter was shot down by the enemy. the single deadliest day for u.s. troops in that war. tonight, we're learning more about who they were, what the mission was. we have two reports beginning with nbc's chief foreign correspondent richard engel in kabul tonight. richard, good evening. >> reporter: good evening, brian. today, the u.s. military released new information about the mission, but there are also now new questions. was it really necessary? before dawn on satury, a senior u.s. military official says elite american army rangers launch an operation to target a taliban leader. it is around midnight, witnesses say, when the rangers arrive by helicopter in the tangi valley, about 60 miles southwest of kabul. they fight hard, a gunfight lasts 30 to 40 minutes, taliban say, before a twin rotor chinook helicopter is called in, full of reinforcements. on board are mostly navy s.e.a.l.s, among america's most highly trained, lethal and secretive troops. nato officials say as the reinforcements arrive at the target, the helicopter is hit by a rocket propelled grenade. witnesses say the helicopter crashes near a riverbed. after it crashed, it caught fire, a huge fire. we were not able to come out during the night because the americans were around. in the morning, we saw the american bodies, he says. chinook transport helicopters are slow and vulnerable when they take off and land. most defenses don't work at close range. 30 americans are killed on the helicopter, including 22 navy s.e.a.l.s. but as details emerge, so do questions, several military analysts with special forces experience wonder why navy s.e.a.l.s were used as backup to catch a midlevel taliban leader in an isolated, mostly unpopulated valley. >> don't forget the s.e.a.l.s are a tier one unit. when we use them they better be going into an area that really justifies their use. >> reporter: it was navy s.e.a.l.s, after all, that killed osama bin laden in pakistan, a mission far clearer, analysts say, than the one that turned out to be the deadliest attack on u.s. troops in a decade of war. u.s. troops here, brian, are in the midst of a gradual drawdown. the problem is the afghan government is not asserting control, so this country is just getting more and more dangerous. >> richard engel starting off our coverage tonight from kabul, afghanistan. richard, thanks. there is one community in particular, in california, that has been hit hard by the loss of so many navy s.e.a.l.s because it is the home of the navy s.e.a.l.s. our pentagon correspondent jim miklaszewski joins us tonight. jim, good evening. >> reporter: good evening, brian. the aircraft carrier "carl vinson" is a clear giveaway that san diego is a big navy town. now beyond that is coronado, where all navy s.e.a.l.s are first born and trained. and today that entire community is in mourning. americans from across the country paid tribute to the fallen heroes, without even knowing their names. in a flash, 30 americans were killed, including 22 navy s.e.a.l.s. like 30-year-old s.e.a.l. aaron vaughn of virginia beach, a bear of a man, with a father's gentle touch. wife kimberly on "today" said his legacy would live through their two children. >> he'll take away his strength, his love for this country, and they will know what an amazing man he is -- was. >> reporter: so many were born to be s.e.a.l.s. kraig vickers of maui, a big man with a big heart. childhood friend moses goods said combat service was in his blood. >> he did the rambo thing. he covered himself in mud, so he was completely camouflaged. and when someone would come by, he would jump up covered in mud. >> reporter: kevin houston wanted to be a s.e.a.l. since the fifth grade. in afghanistan, he always carried this american flag under his body armor next to his heart, except on this final mission. he had sent the flag to his mentor, vietnam veteran christopher kelly. >> when you realize that he wore it on his chest between his body armor on all these missions he was on, it sure was an honor. >> reporter: today, at the special operations command in tampa, defense secretary leon panetta said the nation owes them all the deepest gratitude. >> we will never cease fighting for the cause for which they gave their lives. cause of a secure and safer america. >> reporter: to aaron vaughn's mother karen, it is ironic that while serving in secret as a navy s.e.a.l., it took this tragedy to bring his life to light. >> only in his death can we celebrate who he was in his life. >> reporter: jim miklaszewski, nbc news, san diego. now we turn our coverage to london tonight, where this is a violent time in one neighborhood of that city, another dangerous night of riots and open fires. and nbc's michelle kosinski is there for us tonight. michelle, good evening. >> reporter: hi, brian. the extent of damage at this point is staggering, considering it has been the work of small groups of young men, but in pockets now across the city. and london burns again tonight. look at that. that's a furniture store in the south. but this started on saturday in north london after a peaceful vigil for a man shot dead by police last week, a case that is under investigation. so since then rioters have organized over social media to torch buildings and cars, throw things at police, and loot stores in the middle of the day, everything from sneakers to televisions. the government says that seems to be the main goal right now, calling it sheer opportunistic criminality and thuggery. the perpetrators say it is about anger against police who admit they struggled to control this, calling in now hundreds of reinforcements from outside london. they have arrested more than 200 people. the youngest charged is 11 years old. but it doesn't seem to be slowing down at this point, brian. >> michelle kosinski in our nbc news london bureau tonight. michelle, thanks. when our broadcast continues on a monday night, a woman goes in for chemo, but there are no drugs due to a shortage. and it is happening to thousands of people with all kinds of drugs across the country. and later, "making a difference" for kids who sometimes have to grow up too fast because mom or dad is serving their country. sam higgins... you have frequent heartburn, right ? yeah, it flares up a few days a week. well, we're the two active ingredients in zegerid otc. i'm omeprazole, the leading prescription heartburn medicine. and i'm sodium bicarbonate. i protect him from stomach acid so he can get to work. look, guys, i've already tried a lot of stuff. wow. with zegerid otc, you 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patients and others who need them. it is happening more and more across this country. and our chief medical editor dr. nancy snyderman has more about what's going on and why. >> reporter: when 51-year-old breast and colon cancer patient gail woodish showed up for her regular chemotherapy treatment in november, she was stunned to learn her hospital had run out of her medicine. >> i had already just lost my hair, i had lost my eyebrows, i had so many things going on, i was worried. >> reporter: for gail and her doctor, this was a crisis, and they're not alone. there are now 180 medications on the fda's drug shortage list. that's up from over 56 just five years ago. and it is not just cancer drugs. it is also treatments for heart attacks, pain, even drugs used for anesthesia. >> we do see this as a crisis. it is very hard to see drugs, such as oncology drugs, not available to the american public. >> reporter: how could this happen? manufacturing and quality control issues are factors as are just plain business decisions. drug companies whose medications go generic may decide to stop production to protect their bottom line. and many of these drugs are used on the front lines of america's emergency departments. >> when lives are at stake, that's when minutes count. and that's when er docs get worried. that is what we're concerned about when it comes to drug shortages. >> reporter: for gail woodish, there were no substitutes. she simply had to wait. >> i was angry as well as upset. and then having all of that stress as well was very difficult. >> reporter: the fda says it sometimes is fast tracking the importation of safe foreign medications and pushing manufacturers for earlier notice of shortages. in a statement today, drugmakers emphasized their commitment to maintaining good manufacturing practices and working closely and collaboratively with the fda, supply chain partners and providers. gail eventually got her medicine and is hopeful she can now stay on track. she considers herself one of the lucky ones. the shortage even interfered with clinical trials that may be delayed or stopped because drugs are in short supply. and the fda expects it to get worse, brian, before it gets better. >> big problem. i'm glad we're shedding some light on it here. nancy, thank you as always. she's 61, she's setting out on a second chance to pull off the impossible. of these abandoned racetracks in america today. automotive performance is gone. and all we have left are fallen leaves and broken dreams and -- oh. wait a second. that is a dodge durango. looks like american performance is doing just fine. ♪ carry on. ♪ summertime is now a happy time. when we can eat what we want and sleep soundly through the night. prevacid®24hr prevents the acid that causes frequent heartburn, all day, all night. dr. scholl's custom fit orthotic center recommends the custom-fit orthotic that's best for your tired feet. foot-care scientists are behind it. you'll get all-day relief. for 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[ laughs ] [ male announcer ] make the switch. take action. take advil. want to take just a moment here to remember a number of notable americans we lost over these past few days, including former oregon senator mark hatfield. he was seared by what he saw in world war ii in iwo jima and in hiroshima after the bomb. in the senate, he broke with his party on some big votes. he was a pacifist, a liberal anti-war republican. he called excessive defense spending madness. mark hatfield was 89. bernadine healy died, a harvard educated cardiologist who ran nih and american red cross. she advised three u.s. presidents, a well known media figure in her own right. she resigned from the red cross under pressure for a lackluster performance post 9/11. dr. healy battled brain cancer for over a decade. she was 67 years old. and fred imus has died. don imus' raw, dry, plain-spoken younger brother left a stint in the army to be a brakeman on the southern pacific railroad. he then started up an auto body shop before following his brother into radio. fred imus was 69 years old. "newsweek" magazine is catching heat for a cover photo many consider a cheap shot. calling michele bachmann the queen of rage is one thing, but the photo is clearly a misfire. it received widespread criticism today, some called it biased and insulting. one columnist said she's made to look like there is someone dangling a treat in front of her. several wondered if a male politician would be treated in similar fashion. and texas governor rick perry is emerging as the most talked about gop contender not in the race. this weekend he drew a crowd of 30,000 in houston at a prayer service to pray for our country. he is now off to two big primary states as he considers a run. word from washington tonight that after 200 years, the page program in the house of representatives is ending. both party leaders in the house have decided it is not cost effective anymore. in the electronic age they're just not needed to relay messages as they once were. the senate page program will continue. now, how about something life affirming. diana nyad, a veteran long distance swimmer, is well on her way to setting a new world record, swimming from cuba to the florida keys, without a shark cage. last time she tried this she was 28