At a rally at the University of California, Los Angeles, last Sunday, Elan Carr, the leader of an Israeli diaspora group, told more than 1,000 demonstrators that Jewish mobilization at universities was beginning.

“We will take back our streets. We will take back our campuses from Columbia University to U.C.L.A. and everywhere in between,” Mr. Carr, chief executive of the group, the Israeli American Council, told the crowd.

The U.S. and Israeli national anthems were sung, and there were…