gunned down. the supreme court begins hearing arguments this morning as 26 states challenge president obama's health care overhaul. at the heart of the debate? whether the individual insurance mandate is constitutional. and president obama is joining lead errs of more than 50 nations in seoul, south korea this morning for the 2012 nuclear security summit. the president kicking things off with a stinging warning to north korea. a developing story from afghanistan. nato officials say a gunman wearing an army uniform, an afghan army uniform, killed two coalition members in southern afghanistan before he himself was shot dead. this follows the shooting rampage by a u.s. army soldier that killed up to 17 afghan villagers just earlier on this month. in chile, rocked by a major earthquake, the 7.1 magnitude quake shoot buildings in santiago and triggered a coastal evacuation. three injuries are reported, no major damage however. one minute past 5:00. it's become emotional, it's become racial and political. today thousands are expected to march in the biggest rally yet, a rally for justice for trayvon martin, the unarmed teenager killed one month ago by neighborhood watchman george zimmerman. the march begins with a rally at 4:00 p.m. outside the first united methodist church in sanford, florida. crowds will then make their way to the civic center about a half mile away. it's at the civic center where city officials will be holding a town hall meeting. it's also where trayvon's parents are expected to speak. yesterday worshippers in churches right across the country wore hoodies, something that has become a symbol of the whole fight. cnn's martin savidge is live in sanford, florida, this morning, where they're expecting a lot of people, aren't they? >> reporter: they are, ashley, indeed. the commissioners' meeting had been had on the calendar for some time, but in light of the tragic shooting now they decided to clear the entire agenda, now solely focused on the trayvon martin shooting. they're expecting a very large crowd. they had to move it to the civic center and in fact they believe the civic center could in fact overflow so they're going to set up a jumbotron inside the park where we are right now just in case. it's not just the number of people they're expected to overflow. it's the passion that is also expected to overflow, which is why the family of trayvon martin has put out a statement in advance of tonight saying, please, they ask everyone, be civil to one another. there are concerns that perhaps people's passions, people's emotions could get out of hand at this particular meeting. so everyone is asked to be on their best behavior despite the fact that there are a lot of people who are very, very upset and plan to be there. >> martin, it's one thing to ask people to be on their best behavior and it's another thing to bring out the big guns and start lining the streets with police. do we know anything about the city's plans for additional security today? >> reporter: well, i mean, the only thing we know for certain is, one, they've requested that people act on their best behavior. there will be additional law enforcement standing by, of course, just in case to handle any circumstance that could arise. we also just noticed that a truck has pulled up here with additional fencing. so every precaution the city can take they will take. >> let's hope everything stays peaceful. martin savidge for us in sanford this morning, thank you. also want to let you know that a little later on today brian palmer in "slate" magazine will join us. he's been looking into stories about neighborhood watches and whether or not they have an effect on reducing the crime rate. we'll talk to him at 6:30 this morning. two years after signing his health care overhaul into law, president obama and the american people will soon find out if it is indeed constitutional. the supreme court begins hearing arguments at 10:00 a.m. eastern time. 26 of the 50 states are challenging the measure. it will be six hours of arguments over the next three days. a ruling is expected in june. the individual mandate says most americans must buy health insurance by 2014 or pay a tax penalty. is that constitutional? dan lothian has the very latest for us. >> well, good morning. you know, the white house believes that it is constitutional, and what they're saying and they've been saying now for the past two years is that there are a lot of benefits to it this new law, that young people between 21 and 26 years old who move back in with their parents will be covered, that seniors will have better coverage, and that everyone being covered will bring down the overall cost of health care insurance. but, of course, republicans have been pushing back saying that all of these things that the white house is talking about in terms of the benefits of this new law simply aren't panning out and in the end it will be a much more expensive law. what will be heard in the court today will be what's called the antiinjunction act. essentially, as you pointed out, those who do not take this coverage, which everyone must have insurance coverage by 2014, those who do not will face a penalty of $700 a year. but, of course, since no one has been penalized yet, can, in fact, this be ruled on, the constitutionality of this be ruled on? that's essentially what the court will be looking at today, and, in essence, this could sort of stop the whole case in its tracks, delay it for several years. now, one of the top advisers at the white house, david plouffe, was on "state of the union" yesterday, was asked about what the white house is doing right now to prepare for this case if they do lose. here's what he had to say. >> i don't want to get ahead of the court. we haven't even had arguments yet. obviously the mandate -- >> you've got to be thinking -- >> i don't want to get into -- we're focused right now, our solicitor general going to put forth a very powerful case for why this law is constitutional, why it's important. >> white house officials saying they believe that they will prevail in this case. and, again, they're focused on implementing all the aspects of this new law. again, the coverage whereby everyone must get health coverage won't take effect until 2014. >> dan lothian, live in washington, d.c., thank you very much. seven minutes poost 5:00, and this is about the time we always get that nasty little sign that tells us where the gas prices are today. as if you couldn't guess, sorry, up again. aaa has just announced the national average, $3.90 a gallon. if you're wondering, that's just up three-tenths of a cent but we're less than a quarter shy of the all-time high for gas set back in 2008, which was $4.11 a gallon. gas prices, it's all about where you live. there's several parts of the country, mostly in the west and northeast, where they're already seeing the $4 per gallon and have been for quite some time. sorry to be the bearer of that bad news. kind of feels like groundhog day when we give that one out. >> yes, same thing. seven minutes past the hour here. time for your early start day book, the stories we'll be watching throughout the day. opening arguments are scheduled in a sex case involving two philadelphia priests including monsignor william lynn, the first catholic church official to be tried for allegedly covering up abusive behavior by preeflts. lynn was responsible for investigating reports of sex abuse in the philadelphia diocese. pope benedict xvi visits cuba today on his first trip to spanish speaking latin america. yesterday he led 400,000 catholics in an open-air mass in mexico. just 80% catholic. take a look at the shots. wow. he asked mexican catholics to, quote, boldly promote peace across the country. much to the onlookers' delight, check it out, in the pope mobile he put on asome braer r sombres. that's great. look at those crowds. tim tebow officially arrives in new york city today. the new york jets will formally introduce their new number two quarterback at a news conference at team headquarters in new jersey. the jets acquired tim tebow in a trade with the denver broncos after the broncos signed peyton manning. it's nine past 5:00. still ahead on "early start," we're hearing from the wife of that army staff sergeant accused in the massacre of afghan civilians. we'll find out a little bit about that and also what it's like to be an army wife in this day and age. also some new details about the alleged attack as well. and he has reached the deepest spot on earth. did you know about this? we have an update on james cameron's historic dive seven miles under the sea. got an he tight for "hunger"? apiernlt you're not alone. there were a lot of people who saw this movie. so how did it rate? on the record-breaking scale. we'll let you know how "hunger gai games" pulled offi its weekend. you're watching "early start." not that we'd ever brag about it. turn right. come on, nine. turn left. hit the brakes. huh? how'd that get there? 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[ male announcer ] help your family stay afloat at aflac.com. plegh! so i wasn't playing much of a role in my own life, but with advair, i'm breathing better so now i can take the lead on a science adventure. advair is clinically proven to help significantly improve lung function. unlike most copd medications, advair contains both an anti-inflammatory and a long-acting bronchodilator, working together to help improve your lung function all day. advair won't replace fast-acting inhalers for sudden symptoms and should not be used more than twice a day. people with copd taking advair may have a higher chance of pneumonia. advair may increase your risk of osteoporosis and some eye problems. tell your doctor if you have a heart condition or high blood pressure before taking advair. if you're still having difficulty breathing, take the lead. ask your doctor if including advair could help improve your lung function. get your first full prescription free and save on refills at advaircopd.com. it is 12 past 5:00 on the east coast. time to check the top stories making news with christine romans. >> good morning. the biggest rally planned for trayvon martin today in sanford, florida. the unarmed teen was gunned down by george zimmerman, a man never charged in the death. yesterday church goers across the country wore hoodies to show support and demand justice. george zimmerman's lawyer says the killing was justified saying george zimmerman's nose was broken and back was bruised after he was injured in the confrontation. afghan officials say the u.s. paid $50,000 to the families of each villager killed in the rampage there and $11,000 to those wounded. army staff sergeant robert bales is charged with 17 counts of murder. in an nbc interview, carolyn bales says her husband could never be that cold blooded. >> he loves children. he's like a big kid himself. >> he is accused of killing nine children. >> right. >> innocent children. >> it's unbelievable to me. i have no idea what happened, but he would not -- he loves children and he would not do that. >> meantime, military investigators believe bales carried out the massacre in two phases, returning to his base after the first attack. former vice president dick cheney is recovering from heart transplant surgery this weekend. cheney waited more tran 20 months for a transplant. at age 71 he was nearing the age limit. we'll talk to cnn's senior medical correspondent elizabeth cohen about this in the next hour. moviegoers gorging on "the hunger games." the film opened with a staggering $155 million take at the box office, a biggest opening for a movie not a sequel. if you add in the nearly 60 million it need outside the u.s., "the hunger games" had a weekend haul around the world of almost $215 million. that's a big, big weekend at the box office. >> i've got to see this thing. >> my son went to see it. >> he loved it, right? >> yeah. but he said the book is better. go figure, from my 13-year-old. >> i worry if i go it means i'll have to go to all three of them, right? three or four? whatever it is. i hate being that committed. >> after this weekend, there will be another, i promise you. >> oh, my gosh, unbelievable. >> i think we're on the same track, christina. i go to "lorax," anything that's disney or pixar. >> thank you, christine. let's get a check of your travel weather. here is rob marciano live for us. good morning. >> good morning, guys. that pesky storm that was slowly moving across the country all last week is still affecting the east coast, the back side of which across parts of north carolina. this brought severe weather to the carolinas yesterday and showers across the outer banks but it is slowly moving out to sea finally. we have big changes in the offing. windy in the northeast and finally a dose of march reality, cold temperatures tonight in the 20s and 30s, freeze warnings have been posted for a good chunk of the northeast. then we'll rebound into heat. albuquerque, new mexico, 85 record high, 75 in colorado springs, and in denver, colorado, for record high temperatures. the heat continues across the midsection, a little cooler across the northeast, and a storm system that moved through southern california yesterday heads into the rockies and a fire threat with windy conditions here, gusts 60 to 70 miles an hour, extreme fire danger in denver proper as a matter of fact. we go further out west, or east depending on your perspective, to guam where james cameron got down to the deepest part of the mariana trench there, over 35,000 deep underneath the sea. that is as far deep as mt. everest is tall, actually deeper. it did so yesterday afternoon, about 5:00 or so eastern time. this has been done before, guys, but the first man to do it solo. james cameron obviously a hollywood director but a deep sea diver as well. jason carroll reporting on this a couple of weeks past and he made it down there. >> and he tweeted from down there, rob. >> listen, if you're going to do something, break records, you might as well tweet while you're doing it. >> i can't get reception on metro north. who's getting reception mt. everest deep under the ocean? >> i'm just happy he's okay. we were really worried about traveling solo down there and never making it back up again. so good for him. how exciting. >> thanks, rob. hey, it's 17 minutes past 5:00 on the east coast. and do you know how many people actually paid taxy taxes in thi country? the truth about taxes an who actually pays what. and like an old-school shaq slam dunk, look at this. whoa, the former home of the magic comes crashing down. >> i love that stuff. >> you're watching "early start". >> i can't get enough. >> i don't want to be anywhere near it. welcome back. we are minding your business. u.s. markets closing higher on friday, the dow and s&p 500 up about a third percent. the nasdaq up a little less. stocks are having a strong year so far. there is some concern it's time for a pullback. >> going to bring in christine romans now to talk taxes. 'tis the season. i did the my taxes a couple weeks ago. first time i've ever been early. >> in washington, it's always tax season because we're talking about tax policy and how to change it. you'll hear all these claims that are political. i want to give you a fact check. this is in "money" magazine, very well done. truth or fiction about taxes. you'll hear this a lot, that about half of americans don't pay federal income tax. >> half? >> half of americans. that is actually true. they don't pay federal income tax, 46.4% of taxpayers do not pay federal income tax but they pay payroll taxes out of their paycheck. many of these people are elderly so they don't pay taxz because they're elderly or very, very poor, low income. so when you talk to people about how to broaden the tax base and get more people to pay into the federal coffers, keep that in mind. there's another thing, too. we talk about how warren buffett just paid 17% effective tax rate and that rich people aren't paying their fair share. look at this, the tax rate for the top 400 filers in 1995 was 30%. in 2008, it was 18%. last year it was even less for some because a lot of one-time breaks for all of your investment income. the thing is, the very, very richest people in the country pay less than people who work hard and make money with their hands or their brains because they're making money with their money and that's taxed differently. let's talk about the corporate tax rate. you've heard this so much, that the corporate tax rate is too high and it needs to be lowered. well, the u.s. on paper's tax rate is 39.2%. compare that with the average for all the other rich countries, 29%. but what a company is actually paying is more like 27.7% in this country, pretty much in line with the rests of the world. and guess what, last year they paid even less, more like 12%, because of, again, goodies in the tax code, one-time goodies, meant to help companies. so there is nothing simple about taxes. i've said it a million times. nothing simple about taxes. if you hear from the campaign trail or from politicians that this is it simple, this is how we fix it, just remember -- >> i like you clearing up do half of us really pay no taxes? there's the truth behind the statement. >> absolutely. >> and we all got that big lesson with mitt romney's tax rate that, yes, that's the way it works. sometimes there's a whole different system for tax in businesses, effective tax rates can change. >> making money with money is taxed much, much less. >> christine, thanks so much. 23 minutes past 5:00 on the east coast. we're getting an early read on your local papers. we always get the big old stack and we like to get you up to date. this morning we have the headlines from detroit and atlanta. detroit first, and it ain't good news i hate to say. deadline day in detroit. city leaders there are real worried about their budget and they are scrambling to get some semblance of a financial plan because they're facing a $45 million deficit in the motor city. and guess when they're going to run out of cash. ready? mid next month. the state recommends a fix of -- when i say mid next month, i should correct that. mid-may. about six to eight weeks from now. city is going to recommend a fix of its oven, actually the state, to the governor. but bigger problem here? the detroit mayor is not feeling well. dave bing has been hospitalized. he's had intestinal surgery. he's not sort of there to helm all of. that we'll have to keep an eye on detroit. an investigation uncovers possible widespread cheating on standardized activities in public schools. this is across the country. according to the "atlanta journal-constitution." it's a seven-month investigation. 196 of the nation's 3,125 largest school districts had a high degree, a high degree, of suspicious results on test scores. it suggests cheating but does not prove cheating. most extreme test score swinks in school systems are in baltimore, dallas, d