South Carolina Sen. Lindsey Graham said his party has gone “bat—” crazy as he mercilessly mocked the entire 2016 presidential field, even joking that one could get away with murdering Ted Cruz — if it happened in the Senate.

Graham, who dropped out of the presidential race in December, urged his party to “do a little soul-searching” in his joke-fest Thursday night at the Washington Press Club Foundation’s 72nd Congressional Dinner.

He went on his tear while the remaining Republican candidates clashed in a debate in Houston.

He turned self-deprecating by noting that the dinner was a “good reason not to watch the Republican debate — yet another one I have not been in.”

He then targeted Cruz, the Texas senator who is unpopular among his colleagues.

“A good Republican would defend Ted Cruz after tonight,” he said. “That ain’t happening. … If you killed Ted Cruz on the floor of the Senate, and the trial was in the Senate, nobody would convict you.”

He also made fun of Cruz’s upbringing in Canada, where he was born — which Donald Trump has argued disqualifies him from the high office.

“I know exactly when Ted is going to drop out of the race: March 12,” Graham said. “That’s Canadian week at Myrtle Beach.”

He also teased Democrats in the room — asking House Minority Leader Nancy Pelosi not to leave for the sake of Republicans.

And he took a shot at Hillary Clinton, who may be the next president if Trump wins the GOP nomination.

“The most dishonest person in America is a woman who is about to be president … My party’s gone bats— crazy,” he told the crowed.

He also mocked Clinton’s rocky relationship with White House staffers when she was first lady.

“The only demographic we’re beating her in is the people who take care of the first family in the White House,” he said.

Graham referenced the Justice Department’s probe into how classified material was handled while Clinton was secretary of state.

“I can’t even believe this. The leading candidate on the other side is under investigation by the FBI.”

Graham described retired neurosurgeon Ben Carson as the “nice guy” in the GOP field.

“He tried to kill his cousin,” Graham said, referring to an incident from Carson’s youth. “He’s the one we all like.”