The Supreme Court will ultimately decide on two same-sex marriage cases, but the court's attention-grabbing move has put the pressure on President Barack Obama to clarify his stance on the issue.

When Obama announced in May that he favored same-sex marriage -- after previously supporting just civil unions -- many took it as a full embrace of same-sex marriage rights. It wasn't: his nuanced language stopped well short of endorsing the idea that the U.S. Constitution guarantees a right to marry for same-sex couples. He said the issue was best left to the states to decide in the near term.

But the Supreme Court's decision Friday may have sped up Obama's timeline.

The Obama administration made clear last year that it would no longer defend the Defense of Marriage Act, the 1996 law that denies federal benefits to same-sex married couples. Obama said he'd concluded that law was unconstitutional. It was the Justice Department that asked the Supreme Court to take a challenge to DOMA, hoping justices would agree to strike it down.

However, the federal government has never taken a stand on the other, potentially more significant case that the justices added to their calendar on Friday: the legal challenge to California's ban on same-sex marriage, approved in 2008. In 2010, a district court judge struck down Proposition 8 as unconstitutional and found a broad federal right to same-sex marriage. In February, the U.S. Court of Appeals for the 9th Circuit also found the measure unconstitutional, but on narrower grounds.