John Bacon and Richard Wolf

USA TODAY

Pennsylvania Gov. Tom Corbett said Wednesday that he will not challenge a federal judge's ruling striking down the state's ban on same-sex marriage, saying an appeal is "extremely unlikely to succeed."

Corbett's decision came a day after District Court Judge John Jones declared the ban unconstitutional and said such laws should be tossed "into the ash heap of history."

Unless a higher court intervenes, gay and lesbian couples can marry legally in Pennsylvania, now the 19th state — and the last in the Northeast — to allow same-sex marriage.

Corbett, a Republican, said in a statement that his executive duties "require that I follow the laws as interpreted by the courts and make a judgment as to the likelihood of a successful appeal." But he said he acted against his personal beliefs.

"As a Roman Catholic, the traditional teaching of my faith has not wavered," Corbett said in a statement. "I continue to maintain the belief that marriage is between one man and one woman."

Human Rights Campaign President Chad Griffin said the governor "did the right thing in not standing in the way of thousands of loving couples' ability to make life-long commitments to each other through marriage.

"Breaking down this dark wall of discrimination in the Keystone State strengthens our ever-growing momentum as we continue to expand the marriage equality map."

Tuesday's decision by Jones, who was named to the bench by Republican President George W. Bush, came just one day after a federal judge made Oregon the 18th state where gay men and lesbians can marry. Adding Pennsylvania to the list would mean nearly 44% of Americans live in states where same-sex marriage is legal.

The decision continued a non-stop juggernaut for same-sex marriage since the Supreme Court cleared the way for gays and lesbians in California to marry and struck down key parts of a related federal law last June.

In the past five months, federal judges in 10 states and a state judge in Arkansas have struck down bans on gay marriage. Appeals are underway in Utah, Oklahoma, Virginia, Texas, Michigan, Kentucky, Ohio, Tennessee and Idaho. Eventually, one or more of those cases is expected to reach the Supreme Court — perhaps as soon as next year.

Twenty-one Pennsylvanians sued the state last July for the right to marry there or to have out-of-state marriages recognized. A 1996 state law defines marriage as a union between a man and a woman.

"Plaintiffs suffer a multitude of daily harms, for instance in the area of child-rearing, health care, taxation and end-of-life planning," Jones said in his 39-page written opinion.

He called the couples who brought the case "courageous" and said his ruling brings the court in line with "12 federal district courts across the country which, when confronted with these inequities in their own states, have concluded that all couples deserve equal dignity in the realm of civil marriage."

The state's Democratic attorney general, Kathleen Kane, had declined to defend the law in court. She applauded Jones' ruling on Tuesday.

Corbett took up the case in Kane's absence, with lawyers for his administration arguing that states have the right to determine the definition of marriage. It was not clear, however, whether the politically embattled governor would choose to appeal during what is expected to be a tough re-election campaign.

On Monday, a federal judge in Oregon overturned that state's ban on same-sex marriage, and since state officials declined to defend it, the state immediately became the 18th to legalize same-sex marriage.

The Pennsylvania lawsuit, filed by the state American Civil Liberties Union, claimed that the state's own Defense of Marriage Act and its refusal to marry lesbian and gay couples or recognize their out-of-state marriages violates the fundamental right to marry — and, by discriminating based on sexual orientation, the Equal Protection Clause of the 14th Amendment.

The ACLU had scheduled rallies across the state regardless of the ruling. The decision means those rallies will be celebrations.

Jones concluded his opinion by noting that in the 60 years since Brown v. Board of Education challenged the premise of separate but equal, "'separate' has thankfully faded into history and only 'equal' remains."

He said the term "same-sex marriage" will be abandoned in favor of "marriage" someday.

"We are a better people than what these laws represent," Jones wrote. "It is time to discard them into the ash heap of history."

Contributing: Michael Winter