Al Franken: 'I make fun of the people who deserved it'

Sen. Al FrankenAlan (Al) Stuart FrankenThe Hill's Morning Report — Sponsored by PhRMA — GOP lawmakers race to find an immigration fix Richard Painter puts out 'dumpster fire' in first campaign ad Bill Clinton says 'norms have changed' in society for what 'you can do to somebody against their will' MORE (D-Minn.) says he cracks jokes about political figures for a reason: They had it coming.

"I made fun of the people who deserved it, so Newt Gingrich, I made fun of Rush Limbaugh, and Bill O’Reilly at Fox," Franken told host Stephen Colber on Monday's "The Late Show."

Still, the former "Saturday Night Live" writer said there are several GOP senators who share his sense of humor, including former Sen. Jim DeMint (S.C.) and Sen. Lindsey GrahamLindsey Olin GrahamSenate panel advances three spending bills Trump says he will sign executive order to end family separations Trump backs narrow bill halting family separations: official MORE (S.C.).

Franken recalled telling Graham that he would vote for him in last year's presidential primary if he were a Republican.

"Without hesitation he said, ‘That’s my problem,’ ” Franken said, calling Graham "very funny."

But the Minnesota lawmaker said some Republican lawmakers, like former Sen. Tom CoburnThomas (Tom) Allen CoburnMr. President, let markets help save Medicare Pension insolvency crisis only grows as Congress sits on its hands Paul Ryan should realize that federal earmarks are the currency of cronyism MORE (R-Okla.), haven't initially caught on to his punch lines.

“[Coburn] will admit that he doesn’t have a very good sense of humor so the first three or four interactions we had, we just kind of missed," Franken said.

He said the two men grabbed breakfast one day and Franken cracked a joke that Coburn, a former doctor, completely missed.

"To be a doctor in Oklahoma, do you have to have any formal education?" Franken recalled asking.

Coburn, according to Franken's account, passionately responded: "Yes, you got to go to medical school!"

But he said the meal improved after he "explained to him what jokes were, what the proper reaction to a joke is."

Franken's appearance on the late-night show is part of a string of appearances to promote his latest book, "Al Franken, Giant of the Senate."