At New York University, the police swept in to arrest protesting students on Monday night, ending a standoff with the school’s administration.

At Yale, the police placed protesters’ wrists into zip ties on Monday morning and escorted them onto campus shuttles to receive summonses for trespassing.

Columbia kept its classroom doors closed on Monday, moving lectures online and urging students to stay home.

Harvard Yard was shut to the public. Nearby, at campuses like Tufts and Emerson, administrators weighed how to handle encampments that looked much like the one that the police dismantled at Columbia last week — which protesters quickly resurrected. And on the West Coast, a new encampment bubbled at the University of California, Berkeley.

Less than a week after the arrests of more than 100 protesters at Columbia, administrators at some of the country’s most influential universities were struggling, and largely failing, to calm campuses torn by the conflict in Gaza and Israel.