Rep. Steve King (R-Iowa) talks to voters in Webster City, Iowa, on Nov. 5, 2018. (Scott Morgan/Reuters)

REPUBLICAN LEADERS in Congress are shocked, shocked that their fellow GOP colleague Rep. Steve King (R-Iowa), whose racist remarks have been his political signature for more than a decade, turns out to be . . . a racist. “We don’t take this lightly,” said House Minority Leader Kevin McCarthy (R-Calif.), who has been taking it so lightly for so many years that he hadn’t bothered to notice Mr. King’s toxic utterings until now.

What a difference an electoral drubbing makes. Having lost 40 House seats in the November midterms, the GOP’s congressional capos, including Senate Majority Leader Mitch McConnell (Ky.), seem to be calculating that it may diminish the party’s brand for elected Republicans to demonize, mock, disparage and demean minorities.

With one exception, of course: President Trump.

Bigotry a la Mr. King differs only slightly, if at all, from the pungent dish Mr. Trump has served up for decades — an exhaustively documented litany of slights, put-downs and profiling dating back to the 1970s, when the federal government took action against his company for its attempts to avoid renting apartments to African Americans. Mr. King is ostracized for wondering why it’s offensive to be a white supremacist. Mr. Trump is lionized and feared despite paying homage to the white supremacists who marched in Charlottesville as “very fine people.”

The president’s résumé of racially loaded, coded and hateful commentary is so well known that it often earns no notice from his party’s bigwigs on Capitol Hill; it is a feature, not a bug, of his political persona. Sometimes, some Republicans deign to protest when he oversteps — as when then-House Speaker Paul D. Ryan (R-Wis.) observed that Mr. Trump, then the party’s apparent nominee for president, had rendered a “textbook definition of a racist comment” when he said a federal judge’s Mexican heritage was evidence of his bias.

For the most part, though, Mr. Trump’s bigoted statements are ignored and minimized by Republicans, lest they incur the wrath of the president or his supporters. A small fish such as Mr. King is a different matter: His most recent racist eruption is a vehicle for latent Republican anxiety that the nation’s long-term demographic trends spell trouble for a party whose appeal has narrowed overwhelmingly to whites.

Mr. King has now been disciplined, though the severity of the punishment — he was removed from his House committee assignments, and the House voted to condemn white nationalism and white supremacy — may be lost on some of the voters in Iowa who have sent him back to Washington for nine terms. It’s fine that Mr. McConnell and Rep. Liz Cheney of Wyoming, the No. 3 House Republican, condemn Mr. King. Mr. McConnell’s right that Mr. King should find “another line of work”; Ms. Cheney’s right that his remarks are “abhorrent and racist.”

Will they take notice when bigotry next erupts from 1600 Pennsylvania Ave.?