For two days, Supreme Court nominee Samuel Alito Jr. had insisted to the Senate Judiciary Committee in a dozen different — and sometimes exhausting — ways that his personal beliefs and experiences were irrelevant to how he would judge a case.

But on Jan. 12, his third and final day of testimony, that impenetrable facade broke for a brief, startling moment that said much about Alito. In response to a question about the Court’s affirmative action cases, Alito allowed that a course he taught at Seton Hall Law School a few years ago had convinced him that college classes need to be filled with students from all walks of life.