Graham has emerged as one of Trump's loudest supporters in the Senate amid the House impeachment inquiry.

But his plan to send a letter drew pushback from some of his GOP colleagues during a closed-door lunch last week.

Republican senators warned that the letter could be a distraction and divide a caucus that they felt had otherwise been largely unified so far on their impeachment messaging.

Senators also argued that the letter could highlight perceived splits in the caucus, based on who did or did not sign the letter.

Graham told The Hill last week that he was considering the feedback from his colleagues.

“Some people didn’t like the approach and I’m taking their concerns under advisement. And I’ll do what I’ll need to do,” he said.