(Newser) – Donald Trump's claim that a US-born judge is a Mexican with a conflict of interest is "inexcusable" and "one of the worst mistakes Trump has made," according to Newt Gingrich, a Trump ally so staunch he has been talked about as a VP pick. "That judge is not a Mexican. He's an American," Gingrich tells Fox News. "I hope it was sloppiness." He adds: "If a liberal were to attack Justice Clarence Thomas on the grounds that he's black, we would all go crazy." But Gingrich stresses that he's still impressed by Trump, whom he considers a far better candidate than the "much more flawed" Hillary Clinton. "I'm amazed at his speed, how fast he learns," Gingrich says. "He's a remarkable leader. We have a very good relationship." He says Trump is now at a "turning point" where he needs to run a more disciplined campaign.

Gingrich isn't the only Republican who has taken exception to Trump's remarks on Judge Gonzalo Curiel, who is overseeing two fraud cases against Trump University, and to Trump's suggestion Sunday that he would also consider a Muslim judge biased. "His comments are offensive and wrong and he should retract them," New Hampshire Sen. Kelly Ayotte tells the Washington Post. Paul Ryan and Mitch McConnell have also criticized the remarks. On ABC News' This Week, Clinton denounced the remarks as a "typical Trumpism" and an attempt to deflect attention from "very serious fraud charges" by attacking a distinguished federal judge. "Judge Curiel is as American as I am and certainly as American as Donald Trump is," she said. (Read more Donald Trump stories.)

