Legal insiders knew there would be controversy when Paul Clement, the former solicitor general, signed on to defend the Defense of Marriage Act against constitutional challenge. But few could have predicted a controversy so intense that Clement’s law firm, under fire from gay activists, would abruptly abandon the defense, forcing Clement to resign in protest. And yet that is what happened on Monday. The Defense of Marriage Act, often known by the acronym DOMA, does not outlaw gay marriage, but it allows states not to recognize gay marriages from other states, and it defines marriage for the purposes of federal law as “a legal union between one man and one woman.”

The Act was passed in 1996 by overwhelming bipartisan majorities — 342 to 67 in the House and 85 to 14 in the Senate — and was signed into law by President Bill Clinton. Gay activists have long opposed it, and many hoped that President Obama and congressional Democrats would repeal it. That didn’t happen.