The Supreme Court on Wednesday struck down the federal Defense of Marriage Act, a historic move that significantly expands the rights of gays and lesbians in the country.

The justices ruled 5-4 that DOMA, a 1996 law that defines marriage as the union of a man and woman, is unconstitutional. The result is seen as a long-sought victory for gay-rights advocates who have pushed for the legalization of same-sex marriage.

The high court's ruling doesn't give gays and lesbians the constitutional right to marry. But it keeps state-level same-sex marriage laws in place and set up a legal pathway for more states to do so. (Read the Supreme Court's complete ruling in the embedded viewer below this story.)

While the Clinton and Bush administrations backed the law, President Obama in 2011 instructed the Justice Department to stop defending it. House Republican leadership then stepped in to bankroll DOMA's defense, spending about $3 million.

The law keeps legally married gay Americans from collecting a range of federal benefits that generally are available to married people.