“Sarah Palin was a once-in-a-lifetime situation,” Meyers marveled. “She was incredibly magnetic and came with a built-in catchphrase.”

She, like Joe Biden, inspires what Meyers calls “wet comedy” (as opposed to dry), and they both have what Downey calls “handles,” quirks of speech and personality that both writers and performers can latch onto…

Lorne Michaels, the show’s executive producer, has offered a guest spot to Romney, who is considering it.

“He was funny on Letterman, giving the Top Ten list,” Downey said.

“S.N.L.” has always struggled with its Obama impersonation because Obama is “smooth without big handles,” as Downey puts it. To the dismay of the president, Fred Armisen plays it more as pedantic white guy than cool black guy. In The Times, the writer Jason Zinoman complained: “What’s frustrating about these performances is the same thing that has left many in Mr. Obama’s base disillusioned. Mr. Armisen seems sometimes to blend into the background.”