Sen. Lindsey Graham (R-S.C.) on Wednesday said that he is sending a letter to House Speaker Nancy Pelosi (D-Calif.) warning that Senate Republicans won't impeach President Trump over his call with Ukraine.

Graham, in an appearance on Fox News's "Fox & Friends," said that he was going to ask other Senate Republicans to sign a letter to Pelosi saying that they "do not believe the transcript of the phone call between the president and the Ukraine is an impeachable offense."

"They're about to destroy the nation for no good reason," Graham said. "And I want Nancy Pelosi to know that Republican senators are not going to impeach this president based on this transcript, so she can stop now before she destroys the country."

House Democrats are in the early stages of an impeachment inquiry centered on Trump asking the Ukrainian government to work with his personal lawyer Rudy Giuliani to look into former Vice President Joe Biden and his son Hunter Biden as well as allegations that the president attempted to withhold aid to Ukraine in an effort to get Kiev to launch such a probe.

Trump, according to notes of the call released by the White House, asked Ukrainian President Volodymyr Zelensky to work with Giuliani and expressed hope that he "can look into" Joe Biden's role in the firing of a Ukrainian prosecutor.

"There's a lot of talk about Biden's son, that Biden stopped the prosecution and a lot of people want to find out about that so whatever you can do with the Attorney General would be great," Trump told Zelensky in the July 25 call.

The White House ramped up the fight over the impeachment inquiry on Tuesday, sending a letter to Pelosi and the House committee chairmen overseeing the investigation saying it would refuse to cooperate further with the probe.

In the letter, the White House argued Democrats were pursuing a "constitutionally invalid" investigation of a duly elected president.

Graham, who is one of Trump's most vocal allies on Capitol Hill, blasted House Democrats on Wednesday, saying they couldn't "care less about fairness."

"You have to have a vote to make it legitimate," he added.

Graham, who chairs the Senate Judiciary Committee, announced on Tuesday that he is going to invite Giuliani to testify before his panel. The decision marked a turnaround for Graham, who had previously called for an investigation into "all things Ukraine" but said it needed to come from outside of Congress.

"I think Rudy's got a story to tell. I want him to tell it in my committee. He'd be respectfully treated," Graham said during the Fox News interview. "At the end of the day, I am going to shed a light on all things Ukraine."