PHILADELPHIA — When U.S. District Judge Mary McLaughlin decides this year whether Pennsylvania must recognize same-sex marriages from other states, she’ll do so from her perch above Independence Mall, where about 40 people staged an early gay rights protest in 1965.

For decades afterward, little changed on the marriage equality front. But the cultural and legal landscape has shifted rapidly since 2000, leaving Pennsylvania the last state in the northeast region to ban same-sex marriage.

That could soon change as three high-profile lawsuits move through the courts.

In Philadelphia, McLaughlin is weighing the “marriage recognition” issue, which could reach the U.S. Supreme Court before the broader issue of marriage equality. Her case is set for oral arguments May 28.

“The laws have not caught up to where people actually are on this issue,” said lead plaintiff Cara Palladino, 48, of Philadelphia, a Bryn Mawr University fundraiser who married Isabelle Barker, 42, in Massachusetts in 2005. “When you look around at all the challenges that we have, I think people are increasingly looking at gay marriage as … a nonissue.”

A Quinnipiac University poll last month showed that 57 percent of about 1,400 Pennsylvania voters surveyed approve of same-sex marriage, compared to 37 percent who are opposed.

Lawyers for Republican Gov. Tom Corbett believe the issue comes down to states’ rights — and that neither Massachusetts, nor McLaughlin, should tell Pennsylvania how to define marriage.

“This court should … leave to the individual state legislatures their traditional power, long recognized under the U.S. Constitution, to define the nature and character of the marital relationship within their boundaries,” they wrote in a brief last month in the Palladino case.

It’s not clear whether McLaughlin will rule right away. However, in June, U.S. District Judge John E. Jones is scheduled to hear a broader challenge to the state’s same-sex marriage ban during a two-week trial.

The American Civil Liberties Union represents 25 plaintiffs, including same-sex couples, their children, and a woman who lost her same-sex spouse. They say they have been denied financial and legal benefits that others enjoy. The ACLU plans expert testimony on such subjects as child rearing and the history of marriage, to build a record for the expected appeals.

“We think (they) will demolish any conceivable argument against marriage equality the other side could present,” said Witold “Vic” Walczak, legal director of the ACLU of Pennsylvania.

In a third key case pending in Commonwealth Court, Corbett’s administration has asked a judge to void scores of marriage licenses issued to gay and lesbian couples last year by Democratic local officials in Montgomery County.

“Same-sex marriage is not deeply rooted in our nation’s history … (and) cannot be considered a fundamental right,” attorneys for the state have argued in court papers.

In the Palladino case, Corbett’s lawyers also say the statute of limitations has run, since the couple moved to Pennsylvania eight years ago. In other ways, though, the couple’s timing may be good.

The U.S. Supreme Court last year outlawed parts of the federal Defense of Marriage Act, which defined marriage as the union of a man and woman. And several federal judges this year have knocked down state bans on same-sex marriage.

Malcolm Lazin, executive director of the nonprofit Equality Forum, which is backing the Palladino lawsuit, said there’s been a “sea change” in attitudes toward same-sex marriage. He nonetheless expects any progress in Pennsylvania to come through the courts, not the Republican-controlled legislature.

“Societal changes are happening very, very quickly,” he said, “and they’re all trending in one direction.”

© 2014, Associated Press, All Rights Reserved.

This material may not be published, broadcast, rewritten, or redistributed.