If ever there were a moment for Republicans to jump off the Trump train, now would be as good of a time, according to South Carolina Sen. Lindsey Graham.

Graham wants fellow Republicans who have endorsed Donald Trump to take it all back in the wake of his repeated claims that Judge Gonzalo Curiel's heritage make him unfit to preside over lawsuits against him.

“This is the most un-American thing from a politician since Joe McCarthy,” Graham told The New York Times. “If anybody was looking for an off-ramp, this is probably it,” he added. “There’ll come a time when the love of country will trump hatred of Hillary.”

MSNBC's Joe Scarborough sounded a similar note on "Morning Joe" earlier Tuesday, remarking that senators running for re-election could be forced to reevaluate their stated support of Trump as the party's nominee if he continues to make comments like the ones about Curiel.

"We may be having a two-step process," Scarborough said. "If Trump continues to double down, at some point — for people like Kelly [Ayotte], Ron Johnson of Wisconsin, [Rob] Portman in Ohio — they're not going to be able to endorse a guy that makes racist statements about people born in Indiana."

Vulnerable Republican Senate incumbents have raced to distance themselves from Trump’s rhetoric despite maintaining that they will support him as the party’s nominee.

Ayotte told NBC News on Monday that Trump’s comments are “offensive and wrong, and he should retract them, while a spokesman for Johnson told the Wisconsin State Journal on Monday that the senator “disagrees” with Trump, “just as he has in the past.”

Portman told reporters last Saturday that he also disagreed with Trump’s characterization. “The judge is an American, as I’m an American and as Donald Trump is an American,” the Republican senator said, according to the Cincinnati Enquirer.