What to expect from tonight's debate: a Clinton charm offensive

Tonight's debate is Clinton's to lose.

Tonight's first Democratic debate will be a make-or-break event for all of the contenders. In contrast with the Republican debates, where nearly three dozen people have cast their hat into the ring and all are simply jockeying for recognition, the first Democratic debate may be decisive for all.

LOS ANGELES, CA (The California Network) - The first Democratic debate will feature five candidates in a high-stakes debate. Each one has something to accomplish.

Hillary Clinton, the Democratic frontrunner, has the most to lose, although her inertia, experience and natural talent could carry her through the debate just fine. She is undoubtedly well practiced by now, and the event is hers to lose. With Sanders pledging to refrain from attacking, and the other candidates unlikely to make any meaningful challenge, Hillary just has to avoid gaffes and the debate should be hers.

Bernie Sanders, the only real contender against Hillary, has led a highly-romanticized, meteoric  campaign to actually challenge Clinton. Despite his surge, the fear among his supporters is that he has reached his high-water mark. Even in the past two weeks, he has dipped slightly in the polls. Most Americans have heard of Sanders by now and the Democratic mainstream still supports Clinton.

Sanders has a tall order. Without attacking Clinton, he must convince the mainstream that he's the better candidate. He has higher marks in integrity and trustworthiness. Nobody doubts Sander's sincerity. However, he must also convince voters that he can actually accomplish the job better than Clinton. It's very possible. Sanders is a career politician and he has served very effectively as an Independent. If he can do that from a low position, then he's likely to succeed from a high one too. The challenge, of course, is making the public believe this is possible. Part of that would be to convince people that the right will double down on their anti-Obama strategy, thus stonewalling Clinton's leadership. But there is no mention of this possibility from the Sanders camp.

The first debate will serve as a coming out party for the other challengers. Martin O'Malley, former governor of Maryland, Lincoln Chaffee, former Governor of Rhode Island, and Jim Webb, former senator from Virginia, all have to convince voters that they can be viable and that their vision is better than any of the others. From a national perspective, these men are all dark horse candidates, about which little is known.

All three candidates are regarded as more progressive than Clinton, meaning if they go on the offensive, their target will probably be Clinton. It is from one of these challengers, rather than Sanders, that Clinton could be forced into a blunder.

It is possible they could strike at Sanders too, but he is a much more difficult target because there isn't much to criticize him on. Sanders is a self-professed "social democrat," but young voters are not bothered by the socialist label like older voters may be.

There is one variable that could upset all of the careful calculus surrounding tonight's debate, Joe Biden. The Vice President could possible make a late entry into the debate and throw every candidate into contingency mode. It would be a Hollywood move and a fantastic way for Biden to announce his candidacy. CNN has even brought an extra podium to Las Vegas, just in case that happens.

For his part, Biden would have to board a plane, probably before mid-afternoon in Washington, to make it to Las Vegas to participate. If Biden does not join the debate, then he risks being left out as people start to decide who they will firmly support. Today is his moment, but it remains to be seen if he will take it.