Mr. Bennett, who leads a right-wing religious party, the Jewish Home, which is part of Mr. Netanyahu’s coalition government, flew to Pittsburgh on his own initiative to mourn the victims. While there, he met Jason D. Greenblatt, who serves as Mr. Trump’s Middle East envoy and was taking soundings for a visit by the president.

On Tuesday, Mr. Bennett posted a stream of tweets defending the president, just as Mr. Trump was leaving the synagogue to the distant chants of protesters marching through the Squirrel Hill neighborhood, carrying signs that said “Words matter” and “President Hate is not welcome in our state.”

The next day, in New York, Mr. Bennett continued his defense of Mr. Trump. The president, he said, supported Israel in its battle with Iran and recognized Jerusalem as the capital of Israel. His son-in-law, Mr. Kushner, is Jewish; his daughter Ivanka is a convert to Judaism; and his grandchildren are Jewish, as are many of his advisers.

“What,” he asked, “could be more pro-Jewish?”

Mr. Bennett also cast doubt on a study by the Anti-Defamation League, which claims the number of anti-Semitic incidents in the United States rose 57 percent in 2017, the first year of Mr. Trump’s presidency. “I’m not sure at all there is a surge in anti-Semitism in America,” he said. “I’m not sure those are the facts.”

Mr. Bennett clarified later that he was referring to the number of physical assaults against Jews, not all acts of anti-Semitism. But he also emphasized that anti-Jewish invective comes from a variety of sources, citing Louis Farrakhan, the black Muslim leader who recently posted a video in which he likened Jews to termites.

To many in the American Jewish community, Mr. Trump’s responsibility is clear. Bend the Arc, a progressive Jewish group in Pittsburgh, sent the president an open letter urging him not to visit the city “until you fully denounce white nationalism.”

“Our Jewish community is not the only group you have targeted,” said the letter, which had more than 84,000 signatures. “You have also deliberately undermined the safety of people of color, Muslims, LGBTQ people, and people with disabilities.”