Shake up the next stage of the race for five president ial hopefuls. Seasoned debater Hillary Clinton backed by solid early poll numbers in key states is establishing her presence at these debates. The former secretary of state making an unannounced stop at a yawn union rally at Donald Trumps hotel. I dont think its entertaining when somebody insults immigrants, insults women. If you are going to run for president , then you should represent all the people of the united states. Bernie sanders who has yet to do a mock debate insists hes going to play nice as long as his competitors do. The vermont senator continues to pick up traction, seeing crowds 13,000 strong in tucson, arizona. Lets treat each other civilly. Lets treat each other respectfully and lets not try to demonize people who may have disagreements with us. Reporter a stark contrast to the strategy of their counterpunching republican rivals. Id love to run against her. She is so flawed. I think shes very beatable but she shouldnt be allowed to run. Reporter meanwhile, jim webb, Lincoln Chafee and Martin Omalley have a tough road away, all looking for a breakout moment on a stage. But in a betting town like vegas, anything is possible. Now, the campaigns are keeping their strategies pretty close to the vest. Just like their cards at this point. One thing that Hillary Clintons campaign is saying about her strategy is that she wants to put this email, this benghazi controversy behind her, tray to cut through the politics, Start Talking about her views on the important positions at tonights debate, Bernie Sanders, her main rival at this point, wants to show hes a serious candidate with mainstream views that will obviously be challenged by the participants in this debate. As for jim webb, Martin Omalley, Lincoln Chafee, they have struggled to gain traction in the polls. Theyll be looking for a breakout moment. Who would have known that Carly Fiorina would have had a breakout moment, a strong debate in the last Republican Debate on cnn. That changed the nature of the campaign for her. These lesser known, lesser talked about could have a breakout moment that could change the course of the race. Strong point. Anything. Its vegas. This is going to be spontaneous, live. We wont know until it happens. And it is vegas. Thats all you need to know. What is at stake for each and other tonight . We have seen senior political analyst and editorial director of the National Journal ron brownstein, Cnn National Political Reporter Maeve Reston and cnn politics executive editor mark preston. Weve got ron, reston and preston. Thats who we have this morning. Youre sitting next to me, mark. Give me a little bit of how this sets up atmospherically tonight. How many people in the audience . What do we expect in terms of duration and basic dynamic up there on the stage . A couple things. 1,300 people in the audience. In many ways theyre not just talking to the audience, theyre talking to the viewers. Because this is really the beginning of the campaign. The campaigns been going on and on and on. We havent actually seen them all together, on stage, debate. Theyve been at forums, town halls but they havent interact. Theres a lot at stake for a lot of them, specifically the lowertier candidates, Martin Omalley specifically. Do they have anything to lose . Who do you think has most at stake tonight, maeve . Hillary clinton, obviously. These guys have not been able to really break out beyond Bernie Sanders, up until this point. Theyre going to have to be real fireworks and drama. Martin omalley has been running for a while. I believe hes actually campaigning intensively in the early states. His name recognition has been dropping in some cases. He really does need a shining moment. Theres a very different context for this man the Republican Debate. The Republican Debate, there was a large part of the base angry at the leadership, looking for someone to shake things up. This is the opposite. Democrats have lost the house and the senate. Theyre enormously concerned about putting up the strongest concern that can hold the white house. Its their one leverage of power. This is a parallel audition with the democratic electorate that i am the best nominee as it is a horizontal interaction among the candidates. Above all, i think democrats are looking to be reassured because they have a strong nominee. They are not in a strong position otherwise. Its a very different night. With the republican field they were looking to break out all on the same level, arguably for trump and carson. Each of these people have their own mission. You cant lump omalley, chafee and webb. A big distinction youll see is who decides to talk about the others and who decides to talk to the others on the stage. How does it size up . Whats interesting about that, too, weve seen flares sent up by Bernie Sanders and Bernie Sanders campaign saying im not going to attack Hillary Clinton. Im not going to attack Hillary Clinton unless thshe attacks me. Hillary clinton has to be careful, goes out, talks about the issues, seems president ial. Omalley, he needs to be on the attack. If he doesnt have a breakout moment, his campaign is over. Does she have to explain her flipflops, gay marriage, the keystone pipeline, those things . Its all about her emails. In this sphere its going to be about those changing positions and how she explains tpp, for example, speaking to the labor vote, obviously she was trying to strengthen her hand against Bernie Sanders and also i think the most interesting moment may be on the iraq vote. We know that Bernie Sanders has signaled hes going to go after her on that, talk about his own speech in 2002 where he said it was going to be one of the biggest policy blunders in history. And i think it will be fascinating to see if the democratic electorate, if that issue still resonates as much as it once did. Bernie sanders said he will go after her policies, not after her. Were not expecting any sort of character attacks. Other than maybe the lower three tier might go after bernie or hillary or maybe theyll just talk about the republicans. Yes. I think if you accept the idea that this is mostly almost a parallel audition to be the stander bearer, i think theres incentive for them to go after the republicans. Thats what democrats are looking for. Its easier for the other democrats, including sanders, to go after clinton, than to raise trust issues around the email which will not be well received in a democratic primary context. Hillary clinton will have to answer some tough questions. She has evolved along with the democratic coalition. Shes moved to narrow the issue space for the others to get to her left. In the process, has raised these questions about are you too political, what are your core beliefs . We know shes prepping for the questions about the emails and benghazi. Who decides to bring it up and how. If youre Hillary Clinton, dont you want a question about the email . Dont you want it to come up, this is about as good an audience as youll get to make sure case before those things and not get attacked. Correct. Also, shes going to be testifying before the house next week. Just on the subject. You absolutely want to be in a room of supporters and people who are going to boo if they feel that shes been unjustly attacked. As ron says, this is more of a general election issue, more dealing with independence. Its not a Democratic Party issue. I want to stick with you for one second. I want to talk about the dynamic on stage. They each have one minute to answer direct questions. Right. Then what are the rules of engagement . Can they talk to each other or do they have to wait until their name is mentioned by another one . Right. This is a little bit different than when we saw the Republican Debate in a couple ways. One, theres no donald trump. Very unlikely youll hear his name on stage unless they say that. When i say that, there isnt the acidic personal attacks that weve seen on the republican side. I think trump framed that. You will see crossover in the sense of what separates you from candidate a, candidate b . Or candidate b, this is your policy on keystone, candidate a, you know, thats not your policy, explain it. Although we see Hillary Clinton going on offense after donald trump. Yes. And really inch ing hard. People love to see that. I think we can expect that for sure. Well hear his name but it would be more of a rahrah atmosphere. Across the street we saw the Union Workers. When they break protocol you have to figure out how to reign them in. Sure. More than anybody on the stage, Hillary Clinton has the most at stake because shes got the biggest plus minus on her negative to poll ratio. She has to come out having made the case for herself before this audience of many millions the way she has not to this point. Look, whenever theres an incumbent president in trouble in an election, his supporters always say, its a choice, not a referendum. Then it tornadoes out it really is a referendum, not a choice. That i think is the situation we are in. Hillary clinton, this is a referendum, first and foremost about Hillary Clinton. I think theres a portion of the democratic electorate thats responded viscerally and strongly and probably more than they thought to Bernie Sanders. I dont think you can get to 51 by flanking Hillary Clinton on the left. If there is a way to fundamentally challenge her, its with a majority of democratic voters. If she can answer the questions sufficiently for democratic voters, i think its really hard for anybody else to get past her, just by being more desirable or seeming stronger. But she does also have to show that likable aspect of her personality, that charm. You meet so many democratic voters who have total clinton fatigue and just want something fresh and new. Thats where the ground swell has come for biden. Well see how she does with that. Do you think thats how shes being coached, be as comfortable, relatable, conversational, have zingers. Is that what her handlers are telling her . Right. Lets not forget, shes probably the most skilled debater up there on the stage. She is very good, one of the best politicians in the country. So when she goes up there, if she does something wrong, if she flubs, thats totally on her. Omalley is strong also. He has a great generational place. That is important. That is the lane. That is the argument he can make, the contrast he can draw, a la gary hart in 1984, i am a different generation. One of the obama 2008 aides had an observation, yes, shes a strong debater. Shes strong at speaking to the existing political electorate. Sheds less strong at speaking to the casual voters that are being drawn in, looking for something new and different, something with a little more maybe authenticity. That could be an interesting challenge again. Part of what sanders has to do as obama did in 2008 is bring in, change the democratic electorate if he is going to make a serious run at her. Were going to be watching. Were hearing from the campaigns. Thats always interesting to see where they want you focused going into a big night like tonight. Youll be watching, millions and millions will and this is your first chance to see the big dog democrats right next to each other. The debate tonight 8 30 eastern, right here on cnn. And then of course tomorrow morning, well have all of the debate analysis, what were the big points, what mattered . Who met the bar . Who fell below it. It happens every time. Well have a special one, why sleep we say, 5 30 a. M. Eastern well be right here. I may be in the same clothes. Great thing about it, were in vegas, michaela, where everyone is awake. Its not just us for once. I want to caution you on this. Simi valley an allnighter was a different prospect. Hydrate, pace yourselves and keep your hands to yourselves, christopher. That is not water. This is water. Well look at your headlines here. Back to las vegas in a moment. Breaking news. Multiple stabbing attacks and a shooting reported across jerusalem and Central Israel this morning, killing at least three. Dozens more have been wounded. Erin mclaughlin is live in jerusalem. Reporter michaela, four separate attacks to tell you about, two in jerusalem and two near tel aviv killing at least three israeli civilians. In jerusalem it began in a suburb, a stabbing and shooting attack that happened on a bus, according to Israeli Police. Two attackers involved, one with a knife, one with a gun. At least two civilians killed according to medical services, including a 60yearold man, ten evacuated to the hospital in that attack. Then in an ultrareligious neighborhood in jerusalem, Israeli Police say that around attacker drove his car into a crowd running over three civilians. He got out of his car and started stabbing people. 40yearold man killed in that incident, according to medical services, eight wounded, one seriously. Were also hearing of attacks in tel aviv or near tel aviv. Two attacks in total. One stabbing attack at a bus station or one outsood a rehabilitation center, in total, five israelis injured. The attackers have been identified as two palestinian men from east jerusalem. Theyve been detained. This hour, Security Services are meeting to figure out what to do next and what has been a wave of violence that appears to be getting worse. Calling that violence will be key to them for sure. Thank you for the update. Breaking overnight, Irans Parliament backing the Historic Nuclear Deal with the u. S. Own other world powers but disagreements would arise. Iranian lawmakers are insisting International Inspection of military sites under the pact be approved by a top Iranian Security body. The deal lifts sanctions on iran if the country curbs sensitive nuclear activities. Overnight, two firefighters killed in the line of duty in kansas city. They were battling a fire at an Apartment Building when that structure collapsed. Two other firefighters were injured. Theres no word yet on their conditions, nor the identities of the other victims. Two residents trapped inside their second floor apartments were saved by firefighters on ladders. 15 minutes past the hour. Those are your headlines. Back to chris and alisyn in las vegas. The number six, common or controversial . The answer is, controversial but why . Questioning the decision to have six debates got a prominent member of congress disinvited to tonights events. We have the controversy for you, ahead. To you six is a number to go play right now, by the way. Thats what six means to you. Ill do that. Lucky six. Mes faster than be so he can rapidly prepare his presentation. And when he perfects his pitch, do you know what chris can do . And that is my recommendation. Lets see if hes ready. He can swim with the sharks hes ready. La quinta inns suites take care of you, so you can take care of business. Book your next stay at lq. Com la quinta if i wanhello. O up. Or if i want to go down. No. But then if i want to come back again. Yes. Its perfect. My favorite part is to be able to lift your legs up a little bit and it feels like im just cradled. vo change your sleep, change your life, change to tempurpedic. There you go. We are coming to you live from the wynn hotel in las vegas where final preparations are under way for tonights cnn democratic debate. It is 3 20 here local time. No one in vegas has got than memo. We are at a very active intersection, even at this hour. Tonight is not without controversy. Lets talk about whats going on with lewis miranda, the Communications Director for the dnc. The Democratic National committee and former adviser to president obama. Thanks for being here. Thank you for having me. Can we talk about congresswoman gabbard . Sure. She spoke out about wanting more debates. Youll have a diversity of opinions, whether its about the city we choose for the convention, whether its about the primary and caucus calton der, whether its about the number of debates. We welcome that kind of healthy debate within our party but we want to focus right now on the candidates that are going to be on stage tonight. You were saying earlier this might be the hottest date on record for nevada for this day in history. That i think is going to be because well have a great debate on that stage. Was she actually disinvited. What was asked of her staff is we wanted to keep the focus on the candidates. Thats reasonable. She herself said she felt shed be a distraction even after she was offered an extra ticket and decided not to come. She felt shed be a distraction because shed been disinvited. She was told not to come. Bad move . I think shed be happy that were sitting here looking at what these candidates are going to offer the American People tonight. Theres a lot at stake in this debate and in these coming elections. We have a clip of how gabbard herself explained this. Listen to this. The issue here is not about me saying boohoo im going to miss the party. The issue is one of democracy, of freedom of speech and defending that which so many have sacrificed and given their lives for. She says its an issue of freedom of speech. She wants to be able to say publicly there should be more democratic debates. Shows not alone. Hillary clinton says shes open to that, Bernie San