Even after Obama's unequivocal statement of personal support Wednesday for gay marriage rights - he said the ultimate decision should be left to each state - advocates find it hard to imagine Pennsylvania shedding its socially-conservative stance on legalization anytime soon.
Both legislative chambers are controlled by Republicans, as is the governor's office. And Gov. Corbett, as well as top GOP legislative leaders, have said they oppose legalizing gay marriage.
Twin bills in the House and Senate seeking to legalize gay marriage have languished in committees, with little chance of being brought up for debate there, let alone a floor vote.
Also sidelined: legislation that would amend Pennsylvania's non-discrimination law to include sexual orientation and gender identity or expression as protected classes.
Still, a handful of legislators pushing for gay rights believe the president's Wednesday declaration could break the logjam and ease reluctance to begin debate on an issue many in state politics would rather avoid.
"What the president did yesterday was take a huge step forward," said Daylin Leach (D., Montgomery), the sponsor of the gay marriage bill languishing in the Senate.
During its 15 months of life in a chamber of 50 senators, his bill has garnered all of two other sponsors, both Democrats.
"You can't go back," Leach said. "There will never be another Democratic presidential candidate who doesn't support marriage equality. And it's even going to be more and more difficult for Republicans - you already see that in the muted Republican response to what the president said."
Brian Sims, the Philadelphia Democrat whose April 24 primary victory put him on track to become the state's first openly gay legislator, put it this way on Thursday: "The Republican Party is having to make a decision of relevancy. It is going to have to decide if it is the party of the 1950s or 2050."
Still, a law on the books here since 1996 states: "It is hereby declared to be the strong and long-standing public policy of this Commonwealth that marriage shall be between one man and one woman."
It continues: "A marriage between persons of the same sex which was entered into in another state or foreign jurisdiction, even if valid where entered into, shall be void in this Commonwealth."
Besides the law, there is a bill in the House - also at the committee level - stipulating that the only valid marriage in the state is a union of a man and a woman.
That bill's backers believe Obama's declaration should spur the legislature to finally act on their bill. The legislation - sponsored by Rep. Daryl Metcalfe (R., Butler) and 35 other members of 203-member state House - was scheduled for a vote in committee earlier this year, but was pulled at the last minute.
"There are threats coming to traditional marriage through the court system, through legislation, and now, through what the president said," said state Sen. John Eichelberger (R., Blair), who sponsored traditional marriage legislation in the 2009-10 session. "I would hope people would look at that and say, 'Yes, there is a clear threat, and we have to do something about it'."
Polls suggest a slim majority of Pennsylvanians now tolerates same-sex marriage. a Muhlenberg College/Allentown Morning Call survey conducted late last year found 52 percent of state residents believed it should be legally recognized - marking the first time since the poll began asking this question in 2005 that a majority voiced support.
Six states and the District of Columbia now issue marriage licenses to same-sex couples, according to National Conference of State Legislatures. Two others, Maryland and Washington, have enacted gay marriage laws that have not yet taken effect.
At the federal level, Obama last year directed his Justice Department to stop defending the federal the Defense of Marriage Act (DOMA), the Clinton-era law that defines marriage as between a man and a woman. But that law, too, remains on the books, and overturning it will be difficult without a shift in Congress. For Pennsylvania's senior senator and his Republican challenger, at least, that remains a tough sell.
U.S. Sen. Bob Casey, a generally conservative Democrat on social issues who is up for reelection this year, repeated Thursday what he has said many times: He opposes same-sex marriage, although he favors civil unions to give gay couples some of the legal benefits of marriage.
In 2006, when he was elected to the Senate, there were stories that Casey was having troubles raising campaign funds nationally because he did not toe the line on some liberal Democratic issues. Besides his stance on same-sex marriage, he is generally opposed to abortion.
But Casey said Wednesday that gay-rights activists know where he stands and can see he supports many of their issues: he is pushing for a Senate committee to hold another hearing on gay rights in the work place; and he favors a bill banning discrimination on the basis of sexual orientation by non-religious employers with 15 or more workers.
"I think it's one thing to have a position which is maybe different than some members of the caucus on the issue of gay marriage. It's another thing to have someone," Casey said in reference to his Republican opponent this fall, "who is against all the things I mentioned."
That opponent, Tom Smith, said Thursday he personally opposes civil unions as well as gay marriage. But even Smith, a conservative, echoed a part of Obama's message, saying, "I think that should go to individual states and let the states make the decision."
Smith said he was not familiar with the details of the bill on workplace issues that Casey favors.
"To be very honest with you," the Republican said, "I haven't had an opportunity to read that bill in its entirety, but I support pay equality."
Contact Angela Couloumbis at 717-787-5934 or firstname.lastname@example.org, or follow on Twitter @AngelasInk.
Inquirer staff writer Melissa Dribben contributed to this article.