As Gay Rights Ally, Bernie Sanders Wasn’t Always in Vanguard

As Senator Bernie Sanders tries to distinguish himself from Hillary Rodham Clinton and rally his progressive base, one issue where he has claimed a clear advantage is in the long battle over gay rights.

Mr. Sanders has highlighted his opposition to the 1996 Defense of Marriage Act, which denied federal recognition to same-sex marriages, saying he thought couples should be able to “get married regardless of their sexual orientation.” In a recent interview, he said that “without tooting my own horn,” his opposition to the act, which was signed by...