Sen. Lindsey Graham jokes about 'bat**** crazy' GOP

Sen. Lindsey Graham Roasts Republican Candidates
Sen. Lindsey Graham Roasts Republican Candidates

WASHINGTON, D.C. — Sen. Lindsey Graham mocked all of his former rivals in the Republican race to replace President Barack Obama on Thursday night, joking that his "party has gone bat**** crazy."

Speaking at the Washington Press Club Foundation Dinner, Graham had the harshest words for Sen. Ted Cruz. "If you kill Ted Cruz on the floor of the Senate, and the trial was in the Senate, nobody could convict you," he quipped.

Related: Rubio, Cruz Put Aside Differences and Gang Up on Trump

Graham also went after Sen. Marco Rubio, calling him "the boy wonder," adding: "I'm not saying he would change his positions, but he would change his positions. The Secret Service's main job if he's president is to keep him hydrated."

See more images from Thursday night's debate:

This content is not available due to your privacy preferences.
Update your settings here to see it.

The South Carolina native compared Obama's African roots to Cruz's background. "I will say that our Canadian is better than your Kenyan," he joked. "I know exactly when Ted is going to drop out of the race. March 12 — that's Canadian week in Myrtle Beach, when all of our Canadian friends get 10 percent off."

Referring to the late euthanasia activist, Graham ended his remarks by calling himself the "Dr. [Jack] Kevorkian of the Republican party" because his bid for president failed, and then he endorsed Jeb Bush, who subsequently dropped out.

In an apparent bid to curse the GOP frontrunner, Graham then donned a "Make America Great Hat" and quipped: "I endorse Donald Trump and hope the Graham magic still exists!"

WATCH: Sen. Lindsey Graham goads Donald Trump in baseball cap:

Sen. Lindsey Graham Goads Donald Trump in Baseball Cap
Sen. Lindsey Graham Goads Donald Trump in Baseball Cap

Democratic Sen. Barbara Boxer also joined the fun at the event.

"Have you seen Bernie Sanders' rallies? I haven't seen that many white voters since the Oscars," she joked.

Related: So Long to Lindsey Graham's One-Liners

House Minority Leader Nancy Pelosi joined Graham by weighing in on the Calgary, Alberta-born Cruz's White House bid.

"People are always saying that members of Congress from opposite parties should spend more time after work like we used to do," Pelosi said. "It would be fun to spend more time with Ted Cruz. Don't you think? ... Somewhere where he feels right at home. A Justin Bieber concert, a Toronto Blue Jays baseball game, a maple syrup tasting."

More from NBC News:
Sanders: Congress Would Heed My 'Political Revolution'
Zika Might Cause Worse Birth Defects Than Feared
NY Students Who Claimed Racial Attack to Face Charges