PHILADELPHIA — With separate acts defying Pennsylvania’s ban on same-sex marriage, Attorney General Kathleen Kane and a local official have pushed the contentious cultural issue to the forefront of state politics.

The two Democrats are forcing Gov. Tom Corbett to defend the ban as public support grows for gay marriage, handing their party a weapon with which to try to define the governor and other Republicans as intolerant and out of touch.

Corbett is “on the wrong side of history” and “discriminatory,” the state Democratic Party charged in a YouTube advertisement.

Fifty-two percent of Pennsylvania registered voters supported allowing gay couples the right to marry in a March Franklin & Marshall poll, nearly a complete reversal of public opinion measured by the same independent polling center in 2006.

A state law, enacted in 1996 with bipartisan support, defines marriage as between one man and one woman and says Pennsylvania will not recognize same-sex marriages performed in other states where it is legal.

Last month, Kane declared she could not ethically defend a lawsuit challenging the constitutionality of the statute.

Montgomery County Register of Wills D. Bruce Hanes, calling the ban unconstitutional, has issued marriage licenses to more than 60 gay and lesbian couples in the past two weeks, though they do not have legal effect. Seven couples have married, and the state filed for injunction to stop Hanes.

The stands by Kane and Hanes have sparked debate about marriage as well as fundamental questions about the rule of law and the duty of public officials to uphold it even when they disagree.

Hanes “has blown it up into a political issue at a time when it’s politically disadvantageous for the governor to have to deal with it,” said Montgomery County Commissioner Bruce Castor, a Republican.

Positions on gay marriage tend to break along party and generational lines, according to polls, with Democrats and younger voters more supportive.

Politically speaking, Kane had no real choice but to refuse to defend the state’s ban in court, foisting that task on Corbett’s office, said pollster Terry Madonna of Franklin & Marshall College in Lancaster. Corbett was also in a bind, Madonna said.

“Kane would have sustained some serious political damage as the Democrats’ rising star if she had defended it,” Madonna said. As for Corbett, her predecessor as attorney general, it would have been best if she had taken up the case so he could have avoided the issue entirely, Madonna said.

Now he has no choice but to defend the law vigorously. “Corbett would have had more serious problems with his base because he starts his campaign with almost no support from independent voters, and he needs conservative Republicans to be enthusiastic.”

At the same time, several national polls have shown hints that some Republicans are coming to view the party’s traditional opposition to same-sex marriage as a long-term electoral detriment.

After the party lost two presidential elections in a row, about 60 percent of Republicans say it must change, including reconsideration of some core positions, according to a poll from the Pew Research Center for the People and the Press.

On gay marriage, the poll finds more Republicans say they want the party to moderate its traditional stance against gay marriage than to take a more conservative tack — 31 percent to 27 percent.