“It would show great weakness if Israel allowed Rep. Omar and Rep. Tlaib to visit,” Mr. Trump tweeted on Thursday morning. “They hate Israel & all Jewish people, & there is nothing that can be said or done to change their minds.”

Sad, to borrow one of Mr. Trump’s favorite words. How sad that two leaders — each desperate to look tough to his own base — are risking a bipartisan relationship built between these two nations over generations. Only weak leaders would risk so much for a reward so negligible. To what end? To win a few political points against two of the newest members of Congress? To capture a few news cycles? To dial up the outrage machine just one more notch? Confident leaders would never have risked so much for so little.

Though many American presidents have sought to influence Israeli decisions throughout the history of the Arab-Israeli conflict, they usually did so diplomatically — and to advance America’s interests. Mr. Trump, by contrast, leaned on Mr. Netanyahu as he would on one of his own appointees, in broad view, and in direct violation of what the president of the United States should be doing when democratically elected lawmakers are threatened with a blockade by an allied leader.

There can be, and has been, considerable debate over what the two congresswomen, the first two Muslim women elected to Congress and both sharp critics of the Israeli government, have said and done. They have supported the controversial Boycott, Divestment and Sanctions (B.D.S.) movement aimed at pressuring Israel into ending its occupation of the West Bank, a movement that some Jews have deemed to be anti-Semitic.

Yet, from the outset, Mr. Trump has pounced on the religion and background of the two congresswomen to fan racial divisions. Ms. Omar and Ms. Tlaib were two of the four congresswomen of color, along with Alexandria Ocasio-Cortez of New York and Ayanna Pressley of Massachusetts, who Mr. Trump said should “go back” to the countries they came from, giving rise to chants of “send her back” at a subsequent Trump political rally.