New Jersey Gov. Chris Christie has vaulted into the "top tier" of 2016 Republican presidential candidates, knocking Florida Sen. Marco Rubio down a notch, as he sails to reelection and casts his gaze on the White House, according to the latest rankings from the University of Virginia's political team.

Christie joins Kentucky Sen. Rand Paul as newbies in the top tier along with Wisconsin Gov. Scott Walker, according to the school's "Crystal Ball" predictors Larry Sabato and Kyle Kondik. They report that the recent philosophical battle between Paul and Christie sets up a rare political clash over the direction of the party, and has the result of taking the steam out of Rubio's climb to the top of potential GOP presidential candidates.

More surprising: They report hearing "faint whispers" from some Democrats, especially supporters of President Obama, who are eager to move beyond Hillary Clinton to a new candidate in 2016. Their choice: Recently-elected Massachusetts Sen. Elizabeth Warren.

"We continue to hear faint whispers of opposition to Clinton among some Democrats, particularly among the party's young, Obama-supporting activists. Warren, who has a notably liberal background and who could have the same glass-ceiling shattering effect as Clinton if nominated, is the obvious person to challenge Clinton, if she wanted to. The grassroots on the left would find her an attractive alternative if Clinton is once again viewed as too establishment, or if Bill becomes controversial again -- always a possibility. So we're moving Warren up a notch on our Democratic presidential list," said Kondik and Sabato.

The UVa. team has had Walker in the top tier for a while, believing that he is known as an activist conservative governor who fought and won against unions. "In the event of a Paul-Christie duel (or a battle among others) for the soul of the Republican Party, Walker could present himself as a consensus choice whose nomination would avert a GOP identity crisis," they said.

Other changes in their rankings include moving Texas Sen. Ted Cruz and former Pennsylvania Sen. Rick Santorum up a notch to the second tier of Republican candidates.

Paul Bedard, The Washington Examiner's "Washington Secrets" columnist, can be contacted at