"This will affect the down-ballot races in the Senate and the House and everywhere," Sen. Jeff Flake said. | John Shinkle/POLITICO Sen. Flake urges Republicans to withhold Trump endorsement

GOP Sen. Jeff Flake of Arizona urged Republicans on Sunday not to endorse Donald Trump in the wake of his comments about a federal judge.

"I hope that a number of us at least will withhold endorsement," Flake said on CBS' "Face the Nation." "I've not endorsed, until we see. It's not a comfortable position to not support your nominee of the party."


"None of us want to be in this position," Flake added. "But there are certain things that you can't do as a candidate. And some of the things he's done I think are beyond the pale."

Flake is one of a growing number of Republican members of Congress who have said they don't plan to vote for Trump, including Sen. Lindsey Graham of South Carolina and Reps. Bob Dold of Illinois and Carlos Curbelo of Florida. GOP Sen. Susan Collins of Maine has said she would even consider voting for Hillary Clinton instead of Trump, although she said it was unlikely.

Sen. Mark Kirk of Illinois, who's considered the most endangered Republican up for reelection this year, rescinded his previous endorsement this past week after Trump's attacks on Judge Gonzalo Curiel, who's handling a lawsuit over Trump University. Trump repeatedly said that Curiel was biased against Trump because of his Mexican heritage. (Curiel was born in Indiana and is Mexican-American.)

Trump has said in recent days his comments about Curiel were misconstrued, but Flake slammed him for refusing to apologize.

"Well, to say that his statement was just mischaracterized is wrong" Flake said on CBS. "That statement should be retracted. And he ought to apologize for it."

Flake also voiced support for the "Never Trump" movement's efforts to find another candidate, even as he acknowledged that it was probably too late.

"I doubt that that will gain any speed or currency," Flake told Chuck Todd on NBC's "Meet the Press. "It's pretty much too late at this point to envision another candidate."

Assuming Trump does becomes the nominee, he will hurt other Republicans on the ticket, Flake added.

"This will affect the down-ballot races in the Senate and the House and everywhere," Flake said. "It really has an impact."

Flake himself isn't up for reelection until 2018. "I'm grateful that I'm not running this year," he said.