JAMES CARVILLE

Manager of Bill Clinton's 1992 presidential campaign; CNN political contributor

Extraordinary youth turnout will surprise many, but it shouldn't. Young voters will vote overwhelmingly Democratic up and down the ballot in record numbers. As for a surprise on Tuesday, the combination of Ralph Nader and Bob Barr's votes will affect the outcome of the presidential election in one or more states. We know that Nader cost Al Gore the election in 2000 by siphoning off votes in Florida. The outcome of this election will not be affected -- Barack Obama will be the next president of the United States. But how large will his electoral margin be? Much has been said about the "Bradley effect." I don't necessarily buy it, but why wouldn't voters who won't vote for an African American or a Republican (the GOP brand is at an all-time low), vote for a third-party candidate? Two states where they may have an impact are Georgia and Montana. Only Barr is on the ballot in Georgia, but in a state that only recently became a toss-up, his home-state support could tip the state's 15 electoral votes to either candidate. Their impact on even just a few states will surprise many.