President ial debate. The stage is literally set right behind us. There are the two podiums where Hillary Clinton and donald trump will take their positions in just a short while from now. And the stage is set in every other way in expectations, in stakes, in suspension, in suspense and the importance to the choice voters make in 43 short days. Tonight, a string of new polls shows the race is nailbitingly close for both candidates. Our new nbc News Survey Monkey a fivepoint lead nationally, but other major polls out today show a race virtually tied nationally, and in some key battleground states as well. Some are estimating a total audience on the order of 100 million tonight, and thats super bowl level. And the super bowl is as good a metaphor as any to describe how much is on the line tonight. We have our Political Team assembled and ready to go. Nbcs Hallie Jackson won the coin toss, and she starts us off this evening. Good evening, hallie. Reporter good talk, put it this way, donald trump cannot afford a fumble tonight. A senior aide said the candidate spent the day relaxing, focusing, going over his vision ahead of his first ever oneonone debate. By now trump has seen the stage over where you are, but neither he nor voters have seen anything like whats about to happen. Thank you, everybody. Reporter tonight, despite all his time on tv, donald trump is facing his biggest audience yet, and to prepare, hes doing it like he ys no mock debates, no practice podiums, but hes looked at game tape of Hillary Clintons past debates. Huddling with advisers like chris christie, rudy guiliani, even getting advice from disgraced former fox news head roger ailes. Putting together his playbook. Watch for trump to go after clinton on National Security and foreign policy, strategically inviting a benghazi survivor to join the audience, and two former generals, mother. In his 11 past primary performances, trumps had president ial moments like his rebuke to ted cruz after the senator slammed new york values. We rebuilt Downtown Manhattan and everybody in the world watched and everybody in the world loved new york and loved new yorkers. Reporter but those moments havent lasted. So tonight, thats trumps most important play proving he has the temperament to be commander in chief. Lyin ted, ive given my answer. Reporter insults could backf crooked hillary. Reporter and trumps tendency to fudge facts may put him in risky territory. The Clinton Campaign has been gaining the wrath, been talking to the media for a week now, saying its your job to make sure that donald trump is factchecked in realtime. Reporter trumps aides says hell handle it if clinton comes after his inconsistencies. But if she manages to what trump could do. Always unpredictable, unfiltered. Now under the biggest spotlight of his life. Donald trump comes into the debate with serious questions about his fitness to be commander in chief, questions about his temperament, he needs to show steadiness and the American People need to see someone, if hes going to be successful, who is a plausible commander in chief. Reporter and underscoring the stakes, our new polling shows 34 of americans say tonights debate will be important in deciding their vote. Savannah . Hallie jackson in the spin room, starting us off. Now for how hillary she is an experienced debater, comfortable with the ins and outs of policy, but her challenge tonight, to address issues of character and trustworthiness that have dogged her throughout this campaign. Heres nbcs andrea mitchell. Reporter Hillary Clinton bracing for the biggest moment of her political life, aides say leaving nothing on the table. Even today a lastminute prep session, after latenight mock debates all weekend. Rehearsing at 9 00 p. M. To adjust to the latenight start time, scrappy new yorker playing donald trump. You have 90 minutes and its just a moderator and two of you on stage, you can run but you cannot hide. Reporter even with 40 debates under her belt, tonights challenge for clinton, not knowing which trump will show up. So today shes also prepping for a gracious, polite trump, not the bombastic former reality tv star. I think she needs to be firm, not rude to trump. Out the different views of the country regardless of whether he comes as the nice guy or the belligerent guy. Reporter clintons chief mission, recruiting younger voters. No one has any question about her intellect, her experience, the way she understands the world. What they need to see tonight is more whats in her heart and her gut. Reporter a vulnerability shes struggled with for years. They seem to like barack obama more. Well, that hurts my feelings. [ laughter ] i dont think im enough, hillary. Expect her to hit trump on his temperament, controversial statements about muslims, mexicans, and women and his praise for vladimir putin. Raising the stakes for clinton tonight, new polls showing shes losing ground. Trump has closed the gap in colorado, in a foirway race, now a virtual tie there, and in pennsylvania. A state clinton aides say is their firewall against a trump victory. Her battle plan includes playing mind games with trump, inviting his rival mark cuban to sit in tweet he might invite gennifer flowers. With whom bill clinton once had an affair. Trumps team ruled that out, but today a clinton aide trying to provoke trump, tweeting, if he cant handle mark cuban, how is he going to be commander in chief . Tonight is such a big deal that bill clinton who is nearby and doesnt usually come to the debate hall, may actually show up tonight, aides say. Whats harder to predict are the verbal gaffes or the body voters a lot more about a candidate than all those rehearsed statements. And of course its hard to tell whats going to happen. This is the first president ial debate pitting a woman against a very unpredictable man. Savannah . Andrea mitchell, thank you. We want to bring in our other road weary corresponds, katy tur and Kristen Welker. Katy, who is trump trying to win over tonight . Reporter right now, he has a ceiling of about 40 in the polls and thats not enough to win in nove on those who still have their doubts. How . By not doing what he did in the primaries. By doing the opposite. By not letting trump be trump. Focusing on what he has to offer and avoiding unnecessary attacks on Hillary Clinton, avoiding insults. Proving to moderate republicans and women that hes not a risk. But trump is a wild card and anything can set him off. Thats why you could see his most memorable line, his best zinger in the first 30 minutes of the debate, a headline grabber later on, or a potentially weak showing. Remember, trump doesnt necessarily need to win these voters over. Hell settle on keeping them from voting for Hillary Clinton. Savannah . Katy tur outside the debate hall here. And kristen, as i turn to you, andrea mentioned one of the voting blocks that clinton needs to win over, millenials. So whats the plan . Reporter thats right. Clinton is aiming for undecided and especially younger voters. They were critical to the Obama Coalition in 2008 and 2012. And secretary clinton needs them to turn out in force in order to win the white house. Right now, she is struggling a bit. Remember, during the primary, they overwhelmingly went for senator bernie sanders. Our latest nbc News Survey Monkey online poll shows many of them are leaning toward thirdparty candidates, gary johnson getting 16 of millennial voters. So tonight the strategy is to talk about the issues they care about, issues change, and also jobs. Her other challenge is restoring trust while being relatable to a younger audience when the stakes couldnt be higher. Savannah . Kristen welker, thanks so much. And katy tur as well. A Quick Program guide as we watch tonights debate, its scheduled to last 90 minutes, no breaks. It will be divided into six 15minute segments, the debate topics selected by the moderator, will include americas direction, achieving prosperity and securing america. Hillary clinton won the coin toss and will get the first question. If you notice a difference in those podiums, trumps is, in fact, higher, to make up for the teninch height difference between them. That brings us to moderator of meet the press chuck todd and tom brokaw who needs no introduction. Chuck, as i turn to you, it seems to me, neither candidate is coming in here cruising, hoping for the status quo. They both need to put points on the board. A hundred percent. They dont move the needle that much, that the trajectory of the race isnt changed. But this debate feels different. Theres a lot of fluidity. I think the biggest is the point Kristen Welker was making. Theres one in seven voters right now that say theyre for gary johnson or jill stein. Theres another 10 that are undecided. Theres more fluidity into to this race going into a would argue going back to 1992 since ross perot, and frankly, this is why im looking forward to this debate as much as i was on that one. I dont think weve seen anything like it, nor a political environment like were in. There are real stakes here. Tom, this is a once every fouryear ritual system, why does it feel in m sense historical with these two candidates. They always have a builtin drama. Everything up to this point has been an outoftown tryout. Now theyre on stage. The first woman running for president against a renegade who is a very successful investor in real estate and a Reality Television star who plays by an entirely different set of rules. Its not just what we show tonight. Theres going to be live streaming. People will be on social media. This new environment, atmosphere, that we live in, this universe, theyll have whether they can move the needle or not, i dont know. One thing i know about these debates, they always produce a surprise. Chucks tired of hearing me say this. The ufo is out there. The unforeseen will occur. A good note to leave it on. Thanks so much. Were all going to be here for the debate. Its moderated by our own lester holt, it starts 9 00 eastern, 6 00 pacific. We want to turn to other news now and the horror on the road today in houston. A gunman firing randomly at cars. As people drove to work. Injuring nine. Before he was killed by police in a dramatic shootout. And investigators revealed late today his belongings. We get details from nbcs blake mccoy. The morning commute turned terrifying in this quiet houston neighborhood. A gunman opening fire for 20 minutes. Jeez. Reporter randomly shooting at drivers near a strip mall. I was driving to the gym as usual and suddenly just felt like an explosion inside of my car. And glass everywhere. I heard a few pops, maybe two or three, could smell the powder bullets just flying by. Reporter six people shot, a total of nine injured. The gunman killed in a shootout with police. Multiple officers engaged the suspect, who was shooting randomly at passers by as well as anybody he could put his sights on. Reporter police say he carried out the attack with a militarystyle uniform and nazi emblems were found on some of his belongings. The neighborhood was put on lockdown, jennifer moledas husbands car was hit. She said two bullets went through his windshield, right by his face. He was screaming, crying, im hit, jen, im hit. Reporter police say the shooters car, a black porsche was found nearby. He had two guns and 2,600 rounds of live ammunition. Officials have not named the gunman, but say he was a lawyer who lived in the neighborhood and recently had issues with his law firm. Police say theyre investigating the suspects problems at work and Law Enforcement sources tell nbc news, they do not belie connections to terrorism. With the motive still unclear, this is a Community Shaken and on edge. At least two of the victims remain in the hospital, one in critical condition. Savannah . Blake mccoy in houston for us, thank you. In the midwest, deadly floods have 13 iowa counties under states of emergency tonight. The rivers there are rising. Businesses are submerged as the flood waters move downstream toward cedar rapids. Evacuate. Hundreds of National Guard troops are helping to secure the city and theres more misery to the south in antonio, where torrential rains led to a number of water rescues today. Still ahead here tonight, hail to the king. So many tributes rolling in for golf legend Arnold Palmer. Well have a look back at his amazing life and incredible career on the course. Also from nixons perspiration to gores sigh, the gaffes of debates past that the candidates must avoid here ton approaching medicare eligibility . Dont put off checking out your options until sixtyfive. Now is a good time to get the ball rolling. Consider an aarp Medicare SupplementInsurance Plan insured by unitedhealthcare insurance company. Like any of these types of plans, it could help you with outofpocket medical costs. Call now and request your free decision guide and explore the range of aarp Medicare Supplement plans. Start gathering the information you need. I thought i married an italian. My lineage was the vecchios and zuccolis. Through ancestry, through dna i found out that i was only 16 italian. He was 34 eastern european. 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Switch your business to sprint and save 50 on most current verizon, at t and tmobile rates. Dont let a 1 difference cost you twice as much. Were back now with a tribute to an american icon. Golfing great Arnold Palmer died on sunday in pittsburgh. He was 87. A true class act, palmer was credited with bringing the game out of the country clubs and to the masses. He became a legend over a career that spanned five decades. Nbcs joe fryer now with a look back. Reporter they called him the king. Not the ki quite the opposite. Arnold palmer was the man who took an elite sport and made it a pastime for all. Arnold palmer was the first superstar of the Television Era in golf and he had a personal magnetism that almost burst through a black and White Television screen. A birdie for arnold. Reporter its even said palmer sold a million color tvs, he was that popular, parading across the fairway, flanked by loyal fans, known as arnies army. And what it has meant to me. Reporter his strong yet unorthodox swing was far from textbook, his career was one for the history books. Palmer won seven majors, often battling his oncourse rival and offcourse friend jack nicklaus. When i heard the news last night, i just was crushed. It just sort of felt like a part of my life went with it. We all try, but we all never live up to his standard. He made the difficult look easy. The way for generations of stars, including tiger woods, who says, he meant so much to the game and to me personally. I knew that i could always call him for advice. Palmers legacy never stopped growing, whether through his multi Million Dollar golf empire, or his trademark drink, a mix of lemonade and iced tea. Across 87 years, Arnold Palmer kept his scores below par and his life well above average. And when we come back, with the suspect in a deadly mall shooting revealed, before facing a judge today. Its about moving forward not back. Its looking up not down. 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Ask your healthcare professional if trintellix the suspect in a Washington State mall shooting that left five people dead has reportedly confessed. 20yearold arcan cetin appeared in court today. According to court documents, he admitted entering the mall with the rifle on friday and shooting those five people. He was caught on massive manhunt. The motive is still a mystery tonight. And he faces five counts of murder, bail set at 2 million. The Miami Marlins are taking the field tonight with heavy hearts. Their first game following the death of star pitcher Jose Fernandez in a boating accident. Every player will wear his jersey number, 16, tonight. Fernandez and two others were killed when their boat struck a jedi on sunday morning. The boat was registered to fernandez, but its investigation. Bad weather put a damper on the royal familys visit to canada. William and kate were forced to cancel an aerial tour of a rainforest in british columbia. For Princess Charlotte this is her first royal tour, but all eyes were on older brother george, when he shot down canadian Prime MinisterJustin Trudeaus request for a high five. And when we come back, debate gaffes, those little moments difference on a night like this. . Before it became a medicine, it was an idea. An inspiration. A wild whatif. So scientists went to work. They examined 87 different protein structures. Countless trips back to the drawing board. At first they were told no, well. Maybe, and finally yes. Then it was 36 clinical trials, 8,500 patient volunteers, and the hope of millions. And so after it became a medicine, someone who couldnt be cured, could be. I love that my shop is part of the morning ritual around here. People rely on that first cup and i wouldnt want to mess with that. But when my back pain got bad, i couldnt sleep. I had trouble getting there on time. Then i found aleve pm. Aleve pm is the only one to combine a sleep aid plus the 12 hour strength of aleve. For pain relief that can last into the morning. W im back. Aleve pm for a better am. . . And thats a live look at the stage, hofstra university, the site of what is arguably the most anticipated event in modern political history. With so many eyes on donald trump and Hillary Clinton, the pressure is on to avoid any unforced errors on the debate stage. As our Peter Alexander explains, those unexpected moments can often make or break a candidate. Reporter its the highest of high wire acts, 90 minutes in on this stage, how you appear, sometimes matters more than what you say. Take the first televised president ial debate 56 years ago today. Kennedy looking poised. Nixon famously wiping away sweat. Tonight the debate hall will be cool, including air conditioning vents equally spaced above the candidates. Even the slightest wrong move on stage can leave a mark. Like president bush appearing disinterested, checking his watch. Al gore not faring the Vice President rolling his eyes and engaging in what viewed as intimidation that left some voters unimpressed. To make up for a teninch height difference in this matchup, trumps podium is slightly taller than clintons. Unlike past years, theres no signed agreement between campaigns on mechanics, which Means Nothing stops the candidates from asking each other questions, calling out someone in the audience, or even ultimately one glaring gaffe can bring down an entire campaign. Take gerald ford in 1976, during the cold war. There is no soviet domination of eastern europe. Reporter a good line can diffuse a liability. For reagan, his age. I am not going to exploit for political purposes my opponents youth and inexperience. [ laughter ] reporter tonight after months of fierce attacks, an unpredictable faceoff. Their fit 11 years ago. Peter alexander, nbc news, hempstead, new york. Thats going to do it for us on a monday night. We mentioned the president ial debate airings live right here on nbc, 9 00 eastern, 6 00 pacific. Im savannah guthrie. For all of us at nbc news, thank you for watching, goodnight, and well see you in a few hours. Well see you in aw emily keyes is the name we know, the name we committed to remembering a decade ago this week after the Platte Canyon high school shooting, the gunmans name forgotten long ago. There is another name worth knowing, stacey avila was the Hostage Negotiator on the other side of the door, she never talked about the day until now, the one day in her career she happen. There is evil in this world. And we cant let that direct how we the rest of us treat each other and how the rest of us interact with each other. We have to go past that and help each other and be kind and we supportive of each other and then, you know, just like i and that is how you maintain strength in your life. If you allow a cowered with your gun to take that away, he robbed you twice. Stacey said she learned the lesson from emilys dad, john michael keyes, they travel the country talking School Security and what happened that day. Tonights president ial debate might just be laugh out loud funny, if not for the fact