Representative Ilhan Omar of Minnesota, whose daughter was among the students arrested at a Columbia University protest encampment against Israel’s actions in Gaza, suggested while visiting the protesters on campus last week that some Jewish students supported genocide.

Ms. Omar, a Democrat, was rejecting the argument that the protests were antisemitic, noting that many of the participants were Jewish.

“I think it is really unfortunate that people don’t care about the fact that all Jewish kids should be kept safe, and that we should not have to tolerate antisemitism or bigotry for all Jewish students, whether they’re pro-genocide or anti-genocide,” she said.

Earlier in the week, the Republican House speaker, Mike Johnson, used his own visit to Columbia to suggest that President Biden should summon the National Guard to college campuses, a prospect that brought to mind the National Guard’s killing of four unarmed student protesters at Kent State University in Ohio during the Vietnam War. He was accompanied by his Republican colleague Anthony D’Esposito, who accused the pro-Palestinian protesters of being “proud that you’ve been endorsed by Hamas.”

Representative Jared Moskowitz of Florida, who came to Columbia with other Democrats who support Israel, likened some protesters to the white nationalists who marched in Charlottesville, Va., in 2017.

And at Washington University in St. Louis, the Green Party presidential candidate Jill Stein joined a demonstration and was arrested along with dozens of other protesters.