Lindsey Graham, one of President Donald Trump's staunchest allies in Washington, called the president a "handful" said he may change his mind on impeachment if new evidence of wrongdoing presents itself.

Speaking to "Axios on HBO" on Sunday, Graham said that he was openminded to supporting the impeachment process if evidence of a "quid pro quo" emerges.

"Show me something that is a crime," he told Axios. "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."

Graham also called Trump a "handful" and "an equal opportunity abuser of people."

Though Graham has been one of Trump's most loyal GOP allies, his recent comments suggest that his view of Trump is beginning to slip.

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Lindsey Graham, one of President Donald Trump's staunchest allies in Washington, called the president a "handful" said he may change his mind on impeachment if new evidence of wrongdoing presents itself.

Speaking to "Axios on HBO" on Sunday, Graham said that he was openminded to supporting the impeachment process if evidence of a "quid pro quo" emerges.

"I mean show me something that is a crime," he told host Jonathan Swan. "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 Democrats announced last month that they would launch a formal impeachment inquiry into Trump's activities — in particular, the July 25 phone call between Trump and Ukrainian President Volodymyr Zelensky that is at the center of a whistleblower complaint filed in August.

The intelligence official who lodged the complaint detailed concerns that Trump had pressured Ukraine to aid him politically by investigating former Vice President Joe Biden and his son on allegations of corruption. The complaint was declassified last month, and the White House released a memo summarizing the call that corroborated the complaint.

But Graham told Axios that he did not consider the call between Trump and Zelensky to be enough evidence of an impeachable offense.

"I've read the transcript of the Ukrainian phone call. That's not a quid pro quo to me," he said.

Trump has also asked other countries to investigate the Bidens. During a June phone call with Chinese President Xi Jinping, Trump brought up Biden's political prospects, CNN reported earlier this month, citing two people familiar with the conversation.

Read more: Trump suggests Nancy Pelosi is guilty of treason amid impeachment inquiry

Trump also made a series of comments on the White House lawn calling on China to investigate the Bidens. "China should start an investigation into the Bidens because what happened in China is just about as bad as what happened with Ukraine," he told reporters earlier this month.

"As to asking China to look into Biden, that was stupid," Graham told Axios.

Though Graham has been one of Trump's most loyal GOP allies, his recent comments suggest that his view of Trump may be beginning to slip. Graham has slammed the president's decision to pull US troops out of Syria and called it

"shortsighted and irresponsible."

Graham also told Axios on Sunday that Trump's abandonment of Kurdish allies was "dishonorable" and a "sh-tshow."

"I've got to know him, and I find him to be a handful," Graham said of Trump. "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."