on our broadcast tonight, the showdown at the supreme court. can the federal government be allowed to force every american to have health insurance? breaking her silence. the wife of the american soldier accused in that massacre in afghanistan. talks exclusively to matt lauer. is it a cure for diabetes for those who qualify? stunning news tonight about weight loss surgery. andeep dive. the man who brought us titanic takes his own daring voyage straight down seven miles under the sea. "nightly news" begins now.

good evening. we begin tonight with a basic question for everybody. can congress force you to buy health insurance? more than that, can they charge you a penalty if you choose not to? that question of course is also at the crux of the health plan that may be known forever at obamacare. this is there question the supreme court now gets to answer. they haven't done this often, but they're allowing lawyers to file before them and argue both sides of this case for three days. then they'll decide. because unlike some of the court's decisions, this one will ultimately impact on every last one of us. we begin our coverage tonight with our justice correspondent pete williams at the court. pete, good evening. >> and brian, there hasn't been anything like this in the court's modern history. six hours of courtroom argument this week over a single act of congress. it's a big legal showdown for the signature accomplishment of the obama administration and it's drawing quite a crowd.

outside the court, passionate demonstrations, mostly supporting the law. >> care for you, care for me. care for every family. >> i'm only giving out tickets for today's argument only. >> court officials allowed in 120 of the people who were in line. some of them since friday. >> 24, 25. >> rick santorum even showed up to underscore the political stakes. >> it's a very, very important day for america. >> today's question, can the challengers bring this case now or do they have to wait until 2014? when the centerpiece of the law kicks in, the requirement that all americans get health insurance? >> a 150-year-old law says no tax can be challenged before it goes into effect, and the health care law says anyone who does not get insurance must pay a penalty on their tax returns collected by the irs. so is that a tax? nearly all of the justices appear to think it's not since

the "t" word is not in the health care law. >> congress has nowhere used the word tax. what it says is penalty. and so why is this a tax? >> this is not a revenue-raising measure because if it's successful, nobody will pay the penalty. and there will be no revenue to raise. >> we're done. >> 26 states and a business group are challenging the massive health care law signed by the president two years go, especially its requirement to buy health insurance. they say while the constitution gives congress the power, quote, to regulate commerce, it has no power to regulate people not involved in a commercial transaction. that means, the challengers claim, that congress can't force people to buy something including health insurance. >> if congress could do this here, congress presumably can do this in all sorts of markets where it would be very

convenient to force them into commerce. >> but it regulates the entire health care market. something everyone is involved in. >> congress has found that no one can say that they'll not need health care. that everyone is at risk at every moment. the fact of our mortality as human beings. >> it's clear tonight the court believes it does have the power to decide the issue now. tomorrow, the main question, did the congress have the power to pass this law in the first place, brian? >> pete williams starting off the coverage in the court in washington. pete, thanks. and our legal correspondent savannah guthrie is here with us in the studio for more on this tonight. so, savannah, as a lawyer yourself and a watcher of all things supreme court, i'm already seeing graphics in the newspaper about how this is going to be decided. would we be misinformed to think this is going to fall down traditional lines? >> well, a lot of people suspect this will be a sharply divided court along the idealogical fault lines, but not necessarily. this case really boils down to whether the federal government

exceeded its power under the constitution in regulating in this area of health care. there have been some other recent cases in recent years that presented similar questions of whether the federal government had exceeded its authority and some of the court's most conservative justices, scalia, chief justice roberts, actually voted to uphold the federal law. in other words, they turned down the opportunity to limit the federal government's power. if you go on that, they could vote to uphold the health care law, but as any watcher of the supreme court knows, sometimes the past writings don't dictate what the court will do and it may well be that we see the court strike down what is the president's signature domestic accomplishment legislatively. >> and we'll all know by june. savannah, thank you for being part of our coverage. >> crowds have gathered again tonight in sanford, florida, to support the family of trayvon martin, the 17-year-old shot to death by the neighborhood watch volunteer, george zimmerman, a month ago today, by the way. tonight's rally comes as

zimmerman's version of what happened that night was handed to a local newspaper along with information about a school suspension that trayvon martin's parents have called an attack on their son's memory. our report from nbc's ron allen. >> what do you want? >> justice. >> when do you want it? >> now. >> once again, sanford, florida, is the epicenter of national outrage as trayvon martin's parents delivered 2 million patrician signatures demanding the arrest and prosecution of neighborhood watch volunteer george zimmerman. earlier, they confirmed a news report that their son had been suspended from school for ten days for possession of an empty marijuana bag. they dismissed it as irrelevant to the case. >> they killed my son and now they're trying to kill his reputation. >> they accused the defenders and local police of leaks to the press that corroborate zimmerman's claim that martin attacked him from behind as he returned to his car, knocked him to the ground with a single blow, broke his nose, and then

smashed his head repeatedly on the ground. >> there was a life and death struggle in that instance, and someone was going to die. >> a friend speaking out for zimmerman claims martin was on top when zimmerman shot him in self defense. meanwhile today, thousands demanding justice descending on sanford. some taking buses from hundreds of miles away. police shut down the center of town as crowds filled the civic center to hear martin's family address the city leaders. >> for the sanford police department to feel as if they were going to sweep another young black minority's death under the rug is an atrocity. >> martin's parents maintain their son was trying to get away from a stranger chasing him with a gun. and that zimmerman should not have been acting like he was a cop. >> had he not got out that car, had he not disobeyed the police instructions, trayvon martin

would be living today. >> and as a huge crowd gathering in the park tonight preparing for a rally, watching the proceedings at the council on big screen television, the organizers hope this shows the court for the martin family is even larger than the gathering a few nights ago where 25,000 people were here. through it all, george zimmerman remains in hiding, telling friends he fears for his life. brian. >> ron allen on an otherwise beautiful evening in sanford, florida. ron, thanks. now we turn to the case of u.s. army staff sergeant robert bales, charged last week with murdering 17 civilians in afghanistan. the top u.s. commander there, general john allen said today he's reviewing the command structure of the unit that bales belonged to, looking for what he called potential contributing factors that might have allowed this shooting rampage to take place. this as bales' wife karolyn sat down for an exclusive interview with nbc's matt lauer and told

him she does not believe her husband did what he's accused of doing. >> tell me what you believe. >> i just -- it seems to me like -- i just don't think he was involved. >> so you think this is all mistaken identity? is he being made a fall guy for someone else? >> i don't know. >> 17 people were killed. >> right. i don't know enough information. this is not him. it's not him. >> this is the guy you describe as your best friend. >> right. >> and he's being charged with first degree murder. in other words, premeditated. that he planned this. >> it's very unbelievable. i just -- all i can think of is what happened? what led up to it? i feel like i don't have all of the information. >> he is accused of killing nine children. >> right. >> innocent children. >> it's heartbreaking. it's -- i can't imagine losing

my children. so my heart definitely goes out to them for losing all of their children. >> did he talk about his living conditions over there? what he was doing? >> he said he was always very busy. this mission this time was much more, i think, secretive, what was going on. >> there have been reports, kari, during his deployments in iraq, there were two injuries. he suffered what was called a brain injury. a traumatic brain injury. what can you tell me about that? >> the only time i heard about any of those things is when he got back. he kept a lot from me. >> he suffered a traumatic brain injury, he's communicating with you on a regular basis and you never heard about it? >> no. nope, not until he came back and said he had been blown up. he shielded me from a lot of what he went through. he's a very tough guy. >> do you believe that your husband ever showed signs of ptsd? >> i don't know a lot of the symptoms of ptsd so i wouldn't know. >> is there a question we should

be asking ourselves about the stresses and strains we put our military personnel under through these multiple deployments? >> you have to think they're warriors but they're also human. they're trained to be warriors, to protect our freedoms, and i think people don't see the human side. >> a fascinating conversation, and there is more of matt lauer's exclusive interview with karolyn bales. it's on our website. nbcnightlynews.com. president obama is in south korea tonight, and earlier today, he accidentally let us all in on one of those moments that we know goes on among leaders when they're speaking freely, and he was. because the president clearly had no idea that a microphone could pick up the message he was sending to russian president dmitry medvedev. he's about to leave office and make room for vladimir putin. and the president's comment had

to do with missile defense and his own election back home. >> my last election, after my election, i had more flexibility. >> that conversation took place in seoul at a nuclear security conference, and today, by the way, mitt romney, who wants the president's job, called the comments by president obama an alarming and troubling development. he called the russians our number one enemy, and later thought better of it and clarified his position. the pope is in cuba tonight, and while he's not the first, it's still notable considering the almost 30-year ban on religion there and considering he's been tough on the castro regime. now, he goes about trying to make a more intimate connection to cuban catholics. our chief foreign affairs correspondent andrea mitchell is with us tonight from havana, andrea, good evening. >> good evening, brian. i know you were here the last

time a pope came to cuba. john paul ii, of course. 14 years ago. a lot has changed, and some very important things have not changed here. pope benedict arrived here in santiago, 540 miles from havana. he was greeted by raul castro, dressed in civilian clothes, not the military garb. castro assured the pope that cuba's constitution guarantees religious freedoms. that, of course, has not always been the case. leaving rome this week, the pope pointedly said marxism no longer responds to reality. he was more diplomatic today, expressing sympathy for all cubans, including prisoners. and in fact, cuba's cardinal did negotiate for the release of 130 cuban political prisoners two years ago, and is becoming a powerful if careful voice for political reform today. the government gave people the day off to see the pope's arrival and to attend a mass tonight in santiago. pope benedict doesn't have the charisma of his predecessor, but the pope was showing some style yesterday in mexico. even trying on a sombrero in his

popemobile. and tomorrow, he comes here to havana. he's expected to see both castros, raul and fidel. brian. >> all right, andrea mitchell in cuba tonight. thank you for that. and still ahead as we continue this evening, a big story in health news tonight. weight loss surgery being hailed as a kind of cure for type two diabetes for those who qualify. and later, why a big hollywood name made a dangerous journey nearly seven miles down to the bottom of the world.

as we said, big news in health news tonight and it is this. weight loss surgery may be a cure for people with diabetes, type two diabetes, a disease that an estimated 26 million americans now have. a disease that prestigious new england journal of medicine calls one of the fastest growing epidemics ever. our report tonight on this potentially game-changing

research from our chief science correspondent, robert bazell. >> we're going to do a laproscopic gastric bypass. >> doctors have long known that weight loss surgery can help treat type two diabeteses, but new research at the cleveland clinic has discovered something far more profound. >> it's pretty amazing. many of our patients within even hours of the operation, their blood sugar becomes normal. even before they have lost any weight at all. >> this study and another from the catholic university of rome show the blood sugar decrease lasted so far up to two years and could be permanent. doctors and scientists do not know why the weight lost surgery can have such dramatic effects, but suspect the procedure itself causes massive hormonal changes. >> a lot of research is going on about new operations that are even less invasive and more effective. >> the doctors put 150 patients with severe out of control diabetes in three groups. a third got the best drug therapies, a third got gastric

banding, and a third got gastric bypass. both types of surgery helped, the bypass far more so, eliminating the need for diabetes medications in most patients. for the diabetes treatment, the doctors have been given gastric bypass surgery to patients that are far less obese than the traditional candidates. >> my parents are with me today. >> 30-year-old laura beth lost 70 pounds on her own, but her diabetes did not go away. >> i don't want to be in a wheelchair the rest of my life without my legs or toes, arms. i don't want to be blind. >> she was one whose blood sugar dropped immediately after surgery. the same thing happened for 56-year-old marla evans. >> the diabetes was gone. >> this is an operation that costs about $25,000 with possible dangerous side effects. a worthwhile treatment for severe diabetes? >> i feel 20 years younger.

>> many doctors say yes because diabetes could cost more. and be even more dangerous. robert bazell, nbc news, cleveland. >> former vice president dick cheney is by all accounts resting comfortably with a new heart. he was out of bed, sitting in a chair. surgery was performed saturday after a 20-month wait on the transplant list. his age, 71, puts him at the higher end of the age scale for a heart transplant. this replaces the portable heart bump that had been keeping him alive. the cheney family said they didn't know who the donor was but they said, quote, they would be forever grateful. when we come back, a haunting discovery at sea. and a big shocker in the northeast tonight.

isn't it just like spring to lull you into a false sense of warmth before snapping back? tonight, 18 states are dealing

with the threat of freezing temperatures. 11 are under full-scale frost and freeze warnings from michigan to maine, including places where crops like lettuce and asparagus are already coming up. in buffalo, new york, they're warning tonight of, quote, a widespread, hard freeze expected. bert sugar has died. the man in the hat with the cigar. he was the best known boxing writer in two generations. a pally math, a lawyer, a collector, a prolific author. bert sugar was 75 years old. they are calling it a ghost ship and it's drifting off the coast of british columbia. the experts say it has been on sea for a year since it was on board in the japanese earthquake. officials say it's a squid fishing boat. it's 50 days from reaching shore. they're going to check to be sure it's not leaking fuel. they have warned mariners in the area because you do not want your vessel to come upon that vessel in the pitch black of the

nighttime pacific ocean, and sadly, there are others out there behind it. up next here tonight, hitting bottom with the man who brought us the king of the world.

the film director james cameron of "titanic" fame is famous for his epic movies. he's also a real-life adventurer, and today, he completed a big one. the first solo trip to the deepest part of the ocean, almost seven miles down below the surface of the pacific. his story from mike taibbi. >> for the 57-year-old director, his ride for the trip was a lime green custom designed one man sub he called his vertical torpedo. spinning and descending at 500 feet per minute, and able to withstand an incredible eight tons of pressure per square inch. it took him to the marianna trench. at 35,750 feet down, the very bottom of the pacific ocean floor, some 200 miles west of guam. for cameron and the national geographic society, it was a journey into one of the planet's enduring mysteries. >> jacques cousteau used to say, if we knew what was there, we wouldn't have to go. >> cameron still doesn't know

a lot about what's there. in a short trip, neither here nor his cameras saw any signs of life. >> my feeling was one of complete isolation from all of humanity. >> starting with the "abyss" about a dive team's rescue of a disabled nuclear sub and through "titanic" and then "avatar," cameron has indulged an apparently limitless curiosity about unknown worlds, real or imagined. he emerged from the first go, thrilled to be the first to make the trip solo. in 1960, a two-man team in a more primitive navy sub had done so. and since he had already made over 70 descents in other deepwater subs, he didn't need to parrot a line from one of his famous movies -- >> i'll be back. >> -- since, of course, he will. look for the nat geo special next year. mike taibbi, nbc news, los angeles. >> that's our monday night broadcast as we start another week, and before we go, we want to let you know about an nbc

news initiative in partnership with the u.s. chamber of congress to help america's unemployed veterans get back into the work force. it's called hiring our heroes. there's a lot more on our website, nbcnightlynews.com. i'm brian williams. we hope to see you right back here tomorrow evening. good night. good evening. i'm jessica aguirre. >> and i'm raj mathai. happening right now, a call for justice for trayvon martin. those are the words being heard around the country today and here in the bay area. martin, an unarmed 17-year-old, was shot and killed near orlando last month by a neighborhood watch volunteer. that shooter has not yet been charged and might not be. that's s