Sen. Lindsey Graham (R-S.C.) said Wednesday that he does not feel additional witnesses are needed in President Trump's impeachment trial — despite the Ukraine-linked revelations from former national security adviser John Bolton's unpublished manuscript.

The state of play: In a statement, Graham argued that "one could assume everything attributable to John Bolton is accurate and still the House case would fall well below the standards to remove a president from office."

Republican leadership has moved to avoid calling witnesses, particularly Bolton, hoping to keep the trial short.

But Senate Majority Leader Mitch McConnell told his caucus Tuesday that the GOP does not currently have the votes to block witnesses.

Between the lines: Graham said that he was concerned about Bolton's credibility being attacked, saying "it makes it more likely some will feel the need to call him as a witness."

That's likely a reference to Trump lashing out at Bolton on Twitter on Wednesday morning. The president said the U.S. "would be in World War Six by now" if he had listened to his former national security head during his tenure.

Graham said that if Bolton were called as a witness, then it would be important "to call witnesses on other issues," implying that he'd support pushing for Hunter Biden to take the stand.

Go deeper: Manchin says he believes Hunter Biden is relevant impeachment witness