Photo by Nikki Kahn/The Washington Post)

How will President Obama attack rival Mitt Romney in Monday night’s third and final debate? The president’s debate sparring partner, Sen. John F. Kerry (D-Mass.), offered a preview during a brief talk with reporters in the spin room at Lynn University.

Kerry called Romney and his vice presidential running mate, Rep. Paul Ryan (Wisc.), "the most inexperienced twosome in modern U.S. history to run for president and vice president. They have zero experience in foreign affairs, and there is a lack of clarity in almost anything they've said.”

Kerry played the role of Romney during Obama’s secret prep sessions for all three debates, chosen for his familiarity with Romney’s record as Massachusetts governor and his own experience in the 2004 presidential debates when he was running against then-President George W. Bush.

“Romney’s campaign is trying to say that if he just comes out there and shows he’s competent, he’ll be okay. No, that’s not the standard for commander in chief,” Kerry said. “When I stood up there with George Bush I had to show I had better ideas and show I had specificity… Well, tonight you have to judge the specificity. What does he want to do in Iraq, what does he want to do in Iran?”

Kerry even took a shot at Romney’s summer foreign trip to Britain, Israel and Poland, a jaunt punctuated by several perceived gaffes. Romney offended the organizers of the London Olympics when he questioned whether they were prepared to stage the games and he stated that the sluggish Palestinian economy is plagued more by “cultural” differences than by the strictures of the decades-old Israeli occupation.

“He takes a trip overseas and he trips all over himself from country to country,” Kerry scoffed. “So tonight’s the night of reckoning,” he added. “You can’t just come in here tonight and be a different Mitt Romney. You can’t Etch-a-Sketch your way through foreign policy. You have to have some consistency and precision and it doesn't hurt to have a little bit of experience, instead of none.”

When a reporter asked what adjustments he and Obama made after the president's poor performance in the first debate, Kerry declined to talk about specifics about how they prepared, but used the opportunity to take a couple more digs at Romney.

"I was chosen from binders of senators," Kerry said, making fun of Romney's "binders full of women" comment during the second debate. And in a reference to Romney having once toted his dog in a crate atop his car on a family trip in 1983, Kerry added that he became so good at role-playing Romney that when he went home "my dog was growling at me."