WASHINGTON – In a move sure to please activists who had been frustrated by her conditional support for same-sex marriage, Hillary Rodham Clinton's campaign said she now wants the Supreme Court to back marriage equality as a constitutional right.

Clinton has been a vocal backer of gay rights. But she had hedged when it came to marriage, saying she advocated expansion of marriage rights for same-sex couples on a state-by-state basis.

That changed this week as a Supreme Court case looms in which advocates will ask the justices to strike down the remaining state laws that ban same-sex marriages.

"Hillary Clinton supports marriage equality and hopes the Supreme Court will come down on the side of same-sex couples being guaranteed that constitutional right," Adrienne Elrod, a campaign spokeswoman, said. The shift was first reported by BuzzFeed.

The statement puts Clinton in line with the Obama administration and many other Democrats.

The Supreme Court is scheduled to hear oral arguments on the issue April 28. The justices will consider whether same-sex marriage bans in Ohio, Michigan, Kentucky and Tennessee are constitutional. Gay-rights advocates are hopeful the decision will establish a nationwide right to marry.

The issue has long been a complicated one for Clinton. While first lady, her husband signed the Defense of Marriage Act, a federal law reviled by gay rights groups that allowed states to refuse to recognize gay marriages that took place in other states. The Supreme Court struck down parts of that law in 2013, a move applauded by Clinton at the time.

While secretary of state, Clinton was a forceful backer of gay and transgender rights. But like President Obama, she did not support gay marriage when she ran for president eight years ago. As recently as last year, Clinton stopped short of advocating same-sex marriage as a constitutional right.

"Marriage had always been a matter left to the states," she said last year during a testy exchange on NPR's "Fresh Air."

"I fully endorsed the efforts by activists to work state by state. In fact, that is what is working," Clinton said then. "It is now continuing to proceed state by state. I am hopeful we will make progress and see even more change and acceptance."

In that interview, Clinton took issue with interviewer Terry Gross, who implied that her hedging on the issue of gay marriage was a political calculation. "Just because you are a politician doesn't mean you are not a thinking human being," Clinton said then. "You gather information, you think through positions. You are constantly re-evaluating where you stand."