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 gay marriage front. But the cultural and legal landscape has shifted rapidly since 2000, leaving Pennsylvania the last state in the region to ban gay 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.

It’s not clear whether McLaughlin will rule right away. However, in June, U.S. District Judge John 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.

In a third key case pending in Commonwealth Court, Gov. Tom 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.