People celebrate early election returns favoring Washington state Referendum 74, which would legalize gay marriage, during a large impromptu street gathering in Seattle's Capitol Hill neighborhood, Tuesday, Nov. 6, 2012. The re-election of President Barack Obama and Referendum 74 drew the most supporters to the streets. (AP Photo/Ted S. Warren)

Advocates of gay marriage appear to have made gains both at the U.S. Supreme Court and in Congress this week, as the court’s justices hinted in oral arguments in two different cases this week they would side with same-sex marriage advocates, while a flood of Democratic senators from conservative states joined their liberal colleagues in backing gay marriage.

In oral arguments Tuesday and Wednesday, the Supreme Court, particularly Justice Anthony Kennedy, the critical swing vote, seemed wary of offering a sweeping ruling either affirming or rejecting same-sex marriage. But the justices did not seem inclined to reinstate Proposition 8, the 2008 ballot measure that banned gay marriage in California but has been struck down by federal courts.

And the justices seemed even more skeptical of the Defense of Marriage Act, a 1996 law that defines marriage between a man and a woman, thereby denying same-sex couples federal benefits accorded to opposite-sex couples.

Democrats fall in line on LGBT marriage rights

At the same time, on the political front, a more decided shift towards support of gay marriage continued. While President Obama and many senators from traditionally Democratic states have already declared their support for gay marriage, they were joined this week by Kay Hagan (N.C.), Jon Tester (Mont.) and Claire McCaskill (Mo.), all of whom represent states Mitt Romney won in November, as well as Virginia’s Mark Warner, who has long cultivated a reputation as a centrist Democrat.

The new support illustrated that few Democrats now believe backing gay marriage poses a political risk to them, even if they represent a traditionally-Republican state.

And in Republican circles, opposition to gay marriage appears to be softening as well. GOP senators Rand Paul (Ky.) and Marco Rubio (Fla.), both positioning themselves for potential 2016 presidential runs, have each recently suggested that while they personally oppose gay marriage, the issue should be decided on a state-by-state basis, a shift from the Republican Party’s previously ironclad opposition to gay marriage.

Polls show growing numbers of Republicans under age 50 back gay marriage, particularly those under 30, even as elderly voters still strongly oppose it.

Challenges remain for gay rights advocates

Despite all this momentum for gay marriage, it’s important to note gay it is still banned in 30 states, many of which also bar civil unions.

The Supreme Court sounds like it is unwilling to wipe all of those laws off the books, and the Obama administration and Congress are not pushing any kind of legislation to make gay marriage a national right. And while a pro-gay marriage referendum will likely pass today in Oregon, a liberal state that has still has a gay marriage ban, it’s unclear if a more conservative place like Alabama will soon accept gay unions unless courts force them to.

For now though, the question seems when, not if, acceptance of gay marriage will be allowed throughout America.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr