 -- A prominent U.S. senator from South Carolina said this morning he needs to "re-evaluate" whether he would support Donald Trump as the GOP presidential nominee after comments the real estate mogul made about George W. Bush's actions in connection to the 9/11 terror attacks.

"I've got to really re-evaluate that after what he said about George W. Bush," he said. "There's just the kooky people in the world; the mainstream Democratic party opposition to Bush did not go where Donald Trump went," Sen. Lindsey Graham told “Good Morning America” today.

Graham, who has previously said he will support whoever is nominated, said today he will "have to sit down and think about what it means to have somebody running as the nominee of the Republican Party to accuse the past president of willfully lying about the facts and circumstances of Iraq, and being responsible for 9/11."

"That's something that really only comes from the kook part of America," he said, adding that Trump's reference to George W. Bush as a liar and his administration as the cause of 9/11 is "Michael Moore stuff."

Also, when asked whether Jeb Bush can win South Carolina amid Trump's spiking, Graham said, "Jeb is definitely surging; Donald Trump will not win the nomination.”

On another top topic du jour, Graham said the chances of finding a consensus candidate for the vacancy on the Supreme Court in the wake of Antonin Scalia's unexpected death are "very little. Very small."

"I don't know how that plays out. There's two things going on at the same time. It's very rare that you get a nomination and a selection in the same year. I don't think that's happened very much," Graham said.

As for a consensus candidate, Graham said he himself suggested Sen. Orrin Hatch, R-Utah, but did not seem hopeful about the prospects of a bi-partisan agreement on a nominee.