I was a student at Columbia during the 1968 campus riots. After some days during which students — as well as outsiders who were not members of the university community — took over Hamilton Hall, which then as now housed Columbia College’s administrative leadership, I watched the New York Tactical Police Force enter the campus and proceed not only to arrest students but to beat many of them as well. “Up against the wall motherf---er,” was the favorite police phrase as “New York’s finest” terrorized the students.