Sen. Lindsey Graham, a staunch defender of President Trump, said he would be open to impeachment if proof of what he considers a quid pro quo comes out.

“Sure. I mean … show me something that … is a crime,” Graham said in an interview on “Axios on HBO” that aired Sunday. “If you could show me that, you know, Trump actually was engaging in a quid pro quo, outside the phone call, that would be very disturbing.”

House Speaker Nancy Pelosi launched an impeachment inquiry in September after a whistleblower’s complaint revealed a phone call in which Trump coaxed Ukrainian President Volodymyr Zelensky to investigate corruption during the 2016 presidential election.

Following the complaint, the White House released a rough transcript of the July 25 conversation.

Graham, chairman of the Senate Judiciary Committee, said what was included in that transcript isn’t enough to change his mind.

“I’ve read the transcript of the Ukrainian phone call. That’s not a quid pro quo to me,” the South Carolina Republican said.

The interview with Axios was recorded Tuesday, before acting White House chief of staff Mick Mulvaney told reporters that the administration had held up military aid to Ukraine in exchange for an investigation into the Democratic National Committee‘s server.

But Mulvaney later backtracked and has repeatedly insisted there was no quid pro quo in asking Ukraine to investigate whether the DNC server, which had been hacked by Russia, had been hidden in Ukraine.

Graham’s spokesperson, Kevin Bishop, said Friday that the senator still has not seen anything that rises to the level of impeachment.

Graham, who has joined the president on the golf course numerous times, said he has changed his views about Trump since the 2016 campaign when they were both presidential hopefuls.

“I’ve got to know him, and I find him to be a handful,” Graham said. “I find him to be an equal opportunity abuser of people. But at the end of the day, he can be very charming and be very gracious, and I’m judging him by his conduct.”

He says he continues to back the president because he’s a fellow Republican.

“I like his domestic policies. So you play the ball as it lies,” he said, using a golfing metaphor.

But Graham has been vocal about Trump’s withdrawal of US forces from Syria that opened the door to Turkish President Recep Tayyip Erdogan’s military offensive against the Kurds.

Graham called Trump’s decision “dishonorable” and a “s–tshow.”