House Speaker John A. Boehner brought the Republican-led House into the gay marriage debate Friday by announcing plans to initiate a legal defense of the 1996 law that bars the federal government from giving legal rights or federal benefits to gay couples.

Boehner, an Ohio Republican, seized on the opportunity to take up a social issue after the Obama administration announced last week that its Justice Department would no longer defend the law. The administration concluded that the law, known as the Defense of Marriage Act, was unconstitutional.

If a Republican-dominated House panel agrees to appoint one or more lawyers, as is expected, the GOP would keep alive several pending cases brought on behalf of legally married gay Americans that would otherwise have come to a quiet close.