A Romney aide who asked not to be named in order to preview the debate said that Biden is “an incredibly experienced figure” with a substantial amount of time on the debate stage as well as in the Oval Office and in the White House Situation Room.

“He’s been the president’s strongest surrogate throughout the past four years, and the biggest Achilles’ heel he’ll have is the president’s record,” the Romney aide said.

In a bit of expectations-setting on the Democratic side, an Obama campaign official said that Biden “has been preparing for his debate with Congressman Ryan – a candidate who has an exceptional grasp of policy details and budgetary matters.” The Obama aide also asked not to be named.