WASHINGTON -- The groundswell of support for gay rights grew so strong this week during arguments in two landmark U.S. Supreme Court cases that it flowed across the street to the U.S. Capitol, where just 17 years ago lawmakers voted overwhelmingly to prevent the government from extending numerous federal benefits to same-sex couples.
Four senators who previously opposed gay marriage or were wary of wading into the debate said this week that they now support it.
In Pennsylvania, gay rights activists are discouraged that Sen. Bob Casey hasn't, although he has supported civil unions and laws to prevent employment discrimination against gays and lesbians.
Still, he remains one of only eight Senate Democrats who don't support gay marriage.
The eight are more conservative on that issue than even some Republicans, such as Rob Portman of Ohio, who had been on the short list to be Mitt Romney's presidential running mate.
Mr. Portman recently announced that he had a change of heart on same-sex marriage after talking with his son, who is gay.
Mr. Casey wasn't available for comment, but his office said he is keeping an open mind on efforts to repeal the Defense of Marriage Act, the 1996 law that prevents the federal government from recognizing same-sex marriages.
"He is closely following the debate around DOMA. He intends to thoroughly review any legislation on this when it comes before the Senate," said his spokeswoman, April Mellody.
He may not get a chance to cast a vote if the Supreme Court strikes it down first. That's one possible outcome of oral arguments the Supreme Court heard this week.
However the Supreme Court decides, leaders of Equality Pennsylvania want to hear the state's Democratic senator affirm his support of same-sex marriage.
"We simply want him to say, like these other senators, that he now supports the right of same-sex couples to marry," Ted Martin, executive director of the group, said Thursday.
His advocacy group for gay, lesbian, bisexual and transgender Pennsylvanians is trying to change Mr. Casey's mind with a telephone and email campaign.
Calls and emails are pouring into Mr. Casey's offices in Washington and Pennsylvania.
The effort shouldn't surprise the senator, Mr. Martin said. Equality Pennsylvania has been meeting with him for several months, and he has been willing to listen but hasn't agreed with the group's position.
"He's a good person ... and nothing he's said leads me to believe he isn't listening," Mr. Martin said.
"He has to be evolving. He has to be listening, and this week has really forced everybody to really think about it."
Sens. Kay Hagan of North Carolina, Jon Tester of Montana, Mark Warner of Virginia and Claire McCaskill of Missouri were the latest Democratic senators to come out in support of same-sex marriage.
Mr. Casey hasn't been averse to changing positions on controversial issues in the past.
Outcry for stricter gun control laws after December's school shooting in Connecticut, for example, prompted him to support an assault-weapons ban for the first time.
Bureau Chief Tracie Mauriello: firstname.lastname@example.org, 1-703-996-9292 or on Twitter @pgPoliTweets.