Contest despite some conflicting and curious answers to a question thats left him exposed over very sensitive racial ground. Nbcs katy tur starts our coverage tonight. Reporter tensions high in radford, virginia. Secret service body slamming a time photographer who tried to leave the campaign mandated press pen. Trump on edge, too. This morning blaming his refusal to condition dem the kkk and david duke in a cnn interview on a bad ear piece. Im sitting in a house in florida with a very bad earpiece that they gave me, and you could hardly here what he was saying. Reporter a complaint he did not make during that interview. I dont know anything about david duke, okay. I dont know anything about what youre even talking about with White Supremacy or white supremacists, so i dont know. Reporter trump disavowed the clines infamous former leader last week. David duke and robo calls, White Supremicist movement supporting you. Any words for that . I disavow it and reporter trump cited the onetime grand wizard as the reason he wouldnt run in the Reform Party Ticket in 2000. David duke just joined, a bigot, a racist, a problem, not exactly the people you want in your party. Reporter since he kicked off his Campaign Trump has been repeatedly accused of stoking racial fears, first with mexicans and then africans and muslims. Donald trump is doing his best to appeal to the constituency of david duke and people like david duke while pretending he heegs not doing that very thing. He should be more of a statesman. It wouldnt cost him anything with his supporters, and it hats chance of actually bringing more republicans into his fold. Reporter this weekend trump championed the endorsement of alabama senator jeff sessions, the first u. S. Senator to join trump, this as marco rubio got in the mud. How can a person with the worst spray tan in america . You know what they say with men with small hands. You cant trust them. Reporter hours from super tuesday and for trumps competitors to make their case. I will go to all 50 states and every territory. I will continue to speak out until i literally have no voice left. I will go anywhere to speak to anyone before i let a con artist get ahold. Republican party. Donald trump represents everything youre mad about washington, the dealmaking that doesnt stand with the working men and women. Reporter despite it all, trump is poised to win big. Mexico, everybody talks reporter as you can hear, donald trump is on stage here in georgia behind me. This is another controversy is brewing. Both rubio and cruz calling on trump to press the New York Times to release a transcript of an offtherecord meeting after buzzfeed reported that trump may have expressed flexibility on his hardline immigration plan. Lester . Katy tur tonight, thanks. As the trump train rolls into super tuesday full of steam, some Republican Leaders are now openly expressing deep concerns about the prospect of donald trump as the partys nominee. Saying he wont support him, and as nbcs Andrea Mitchell reports, the anxiety pitch. We have a movement going on. This isnt normal. Reporter donald trump packing in again today, but behind the scenes nbc news has learned trump has many Top Republican officials scrambling, looking for a way to block him from getting the nomination. A lot of people who are worried donald trump cant win in november. New poll out today that shows that hes behind Hillary Clinton where in almost every other poll, virtually any other republican beats Hillary Clinton so theres concern there. Reporter adding to the alarm, trumps response on the ku klux klan, prompting this tweet from 2012 nominee mitt romney. A disqualifying and disgusting response by real donald trump to the kkk. His coddling of repugnant bigotry is not in the character of america. Are we choosinging a president like American Idol . Is that the system and what kind of democracy theres a lot of people i think legitimately worried. Reporter one big concern for republicans, would trump at the top of the ticket, if he loses, take down with him 24 gop senate candidates, and tonight the first republican senator to say he wont vote for trump if hes the nominee. Nebraskas ben sass. In a Facebook Post he wrote conservatives will need to find a third option other than trump. This is a guy who says things again and again that sound a lot more like Vladimir Putin than abraham lincoln. Reporter there are two key worries among Many Republican officials if trump gets the nomination. First, if he wins in november, would he govern as a conservative . And, second, would he even get that far . If democrats are able to successfully attack his past statements and his business record. Lester . Andrea mitchell, thanks so much to talk about. Lets bring in our political director, the moderator of meet the press, chuck todd. Chuck, if trump does well tomorrow, what are the points in which they can other republicans can stop him . Can stop him within the party is to deny him the delegates he needs to get the nomination. To do that, he does well tomorrow night, then it becomes imperative that they defeat trump in march 15 in ohio meaning every other candidate other than john kasich decides to campaign there. Maybe rubio says ill let kasich go there and rubio has to win his home state of florida and maybe they find somebody else to rally around and beat him in illinois and north carolina. Thats the only way they can do it within the party, but if they dont succeed by march 15th, theres nothing they can do, cant deny the nomination so then its the thirdparty route. Ive heard rumors of finding a candidate, mitt romneys name. Theres a Constitution Party out there that has ballot access. If they want to start a third party, youd have to do it within the next couple of weeks to actually get ballot access, but this stuff is real, and it gets very real on march 16th if donald trump continues to roll. Havent ever seen anything like it. Not since 1860 and the wigs. Was born out of another conservative party the whigs breaking apart. Maybe history is truly repeating it self. Chuck todd, thank you. On the democratic side fresh off her landslide victory over Bernie Sanders in South CarolinaHillary Clinton is look ahead to super tuesday as an opportunity to pull away in this race. Nbcs Kristen Welker is with the Clinton Campaign in virginia. Kristen kristen, what can you tell us. Reporter lester, good evening. Clinton Campaign Officials say they feel confident heeding into super tuesday after that big win in South Carolina, fueled largely by africanamerican support. Clinton hoping to build on that tomorrow. Senator sanders vowing not to give up, but he does have a steep climb, particularly if you look at the numbers, lester. The official nbc news delegate count shows clinton with 519 delegates and sanders with 86. If you only take into account super delegates, typically Party Leaders who get to choose who they will support, clinton gets 428 to sanders 21, a 20field clinton is up with ads in all of the super tuesday states and sanders with ads in five of them, smaller, less diverse states massachusetts. Still, sanders has a lot of cash on hand which means no matter that could allow him to stay in this race lester . Kristen welker tonight, thank you. For many of you the stations will be carrying the live hourlong editions of nightly news with all the results as they come in and special primetime coverage across the country starting at 10 00, p. M. Eastern time. There were terrifying moments today inside an ohio school when police say a teenaged student opened fire hitting few students and injuring two others. Tonight the suspect is in custody as students and their parents cope with the aftermath. Nbcs blake mccoy now with details. Reporter it was in the cafeteria of Madison Junior Senior High School where Authorities Say a his classmate. One student managing to call 911 from a high school. Im at madison high school. Theres a shooting. Okay. Hes got a gun. He started shooting people. How many people did he shoot . Im not sure. He just pulled out his gun and started shooting. Reporter two students shot at lunchtime, two others injured in the chaos. The school put on lockdown as frantic parents raced from work. We had to get here. Had to get to him. Serious mindset and just trying to be quiet and keep everybody else around me safe. Reporter cool is in middletown, ohio, about an hour north of cincinnati. The two students shot, 14 and 15yearold boys, were flown by helicopter to the hospital. They are both basically stable at this time. Reporter attention now turns to the accused shooter, a 14yearold male who police say tossed the handgun as he ran from the building. Hes been charged with two counts of attempted murder, a motive unknown at this time. Gag to be hard for reporter class has been cancelled across the district tomorrow as parents hold their kids tight. Blake mccoy, nbc news. Late word that Sports Reporter erin andrews is on the stand tonight in her 75 million civil trial. Earlier in the day the man convicted of stalking andrews testified. He told the court how he altered the peep hole on Andrews Hotel door and secretly filmed her. Now as nbcs Morgan Radford reports, its andrews turn. Reporter erin andrews still haunted by the video that she says has damaged her career. I feel so embarrassed and im so ashamed. Reporter her chance to look jurors, seven women and five men in the eye and tell her side of the story. My naked body was on the front page of the New York Post and they put bars over my body parts. My girlfriend is calling me and telling me she was running around new york city throwing coffee on all the pains because she felt so bad. Reporter just hours earlier andrews her stalker explained the sordid details of the day he secretly recorded her. I could hear the shower on in her room and i walked by. Reporter and Michael Barrett explained how he followed andrews to her Nashville Hotel room and altered the peep hole. I pulled the plug out and waited for the opportunity. Reporter was it your intent to hopefully get her without clothes on . Yes. Reporter her mother paula also testified today describing the embarrassment her daughter continues to face. Its a nightmare that doesnt stop. I just kept telling her its not your fault. Youre a vicity. Youve been youve been assaulted. Reporter andrews devastated. Its so embarrassing. It was my private time. I never thought something would happen. I never thought a hotel would let somebody next to me without telling me. Reporter andrews says her entire life is different now and that this ordeal is erin says that she continues to be haunted on a daily basis, and as for barrett he lives in oregon and his Internet Activity is monitored by a patrol officer. Lester . Morgan radford, thank you. At the white house today a member of the elite s. E. A. L. Team 6 received the medal of honor and because missions are covert and highly classified we rarely see their names or see their faces. Today one stepford. Nbcs Jim Miklaszewski has the story of his incredible bravery. Reporter as a navy s. E. A. L. Senior chief ed buyers rarely emerges from the shadows and one of the silent warriors from s. E. A. L. Team 6, the special Operations Force that previously took down osama bin laden, but today in a rare appearance buyers was front and center at the white house, an american hero. In december 2012 the s. E. A. L. Ran a mission to rescue an american hostage joseph taken hostage by the taliban. As they approached the exploded. It was pitch black and everything happens in a hostage rescue scenario happens really fast. Reporter petty officer nickless cev was first through the door and fatally wounded. Nick died, you know, a warriors death, died a true american hero. Reporter buyers was seconds behind and took out taliban shooter. He had a weapon about, you know, level, ready to shoot, and fortunately i was just quicker on the draw on that. Reporter buyers spotted the hostage on the floor and threw himself on top of the american. You were willing to take a bullet for that hostage . Thats our job, yes. Reporter buyers then grabbed another taliban fighter by the throat. Just gave it enough time for my teammates to come in and get in position to take care of that threat. In times of war uncertainty, theres a special breed of warrior ready to answer our nations call. Reporter president obama presented buyers with the medal of honor which he accepted not for himself but the entire its for the brotherhood, its for everything that we have sacrificed since 9 11 in defense of our country. Reporter Jim Miklaszewski, nbc news, the pentagon. Theres a lot more to tell you about as we continue on this monday night. Still ahead, losing sleep and gaining weight. More word on what could be fueling the junk food cravings. And rock the stage, those expecting what sore elbow . Advil liquigels make pain a distant memory nothing works faster stronger or longer what pain . Advil. Theres only one egg that just tastes better. With 10 times more vitamin e. And twice the omega 3s. Because why have ordinary when you can have the best. Only egglands best. Better taste. Better nutrition. Our parents worked hard so that we could enjoy lifes simple pleasures. Now its our turn. Im doing the same for my family. Retirement and Life Insurance solutions from pacific life can help you protect what you love and grow your future with confidence. Pacific life. Helping generations of families achieve if youre one of the millions of people who would like to lose a few pounds and are struggling, new Research Suggests part of the problem may be with how much sleep youre getting or not getting. Onethird of adults get less than six hours of sleep a night rather than the repgd seven to eight hours. It turns out the less we sleep, the more we crave food and not the foods that are good for us. As nbcs tom costello reports. Reporter they are two of americas biggest complaints, a few extra lbs around the midsection and not enough sleep. I definitely dont get as much sleep as i would like to get. Some nights i do. Some nights i dont. I dont get as much sleep as i would like. As soon as i wake up i feel like im starving and all i want is food. Reporter new research from the university of chicago shows it may be part of a vicious cycle. The less sleep we get the more our produce produce a chemical in the blood that increases our cravings. The same system triggered by marijuana. Cravings for the sweets, salty and on in the afternoons and evenings. Were actually eating more calories than needed for energy costs of being awake longer. Reporter previous studies have found when sleepdeprived adults got an extra hour and a half of sleep a night, the recommended eight hours, the cravings for junk food dropped. People who get less than six hours are at an increased risk of obesity. This dock getting 300 calories a day is two cookies in two weeks can be a pound of extra fat. Reporter just two weeks. Two weeks. Reporter best advice, go to bed and wake up at the same time every day and avoid eating anything in the two to three hours before going to sleep. If junk sleep leads to junk food which leads to obesity and more junk sleep, breaking the cycle could be key. Tom costello, nbc news, washington. Were back in a for adults with an advanced lung cancer called squamous nonsmall cell, previously treated with platinumbased chemotherapy, its not every day something this big comes along. A chance to live longer with. Opdivo, nivolumab. Opdivo is the first and only immunotherapy fda approved based on a Clinical Trial demonstrating longer life. For these patients. In fact, opdivo significantly increased the chance of living longer versus chemotherapy. Opdivo is different. It works with your immune system. Opdivo can cause your immune system to attack normal organs and tissues in your body and affect how they work. This may happen any time during or after treatment has ended, and may become serious and lead to death. See your doctor right away if you experience new or worsening cough; chest pain; shortness of breath; diarrhea; severe stomach pain or tenderness; severe nausea or vomiting; extreme fatigue; constipation; swollen ankles; loss of appetite; rash; itching; headache; confusion; hallucinations; muscle or joint pain, or flushing as this may keep these problems from becoming more serious. These are not all the possible side effects of opdivo. Tell your doctor about all your medical conditions, including immune system problems, or if youve had an organ transplant, or lung, breathing, or liver problems. A chance to live longer. Ask your doctor if opdivo is right for you. Bristolmyers squibb thanks the patients and physicians who participated in the opdivo Clinical Trial. A heart attack doesnt care if you run everyday, or if youre young or old. 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