The American Civil Liberties Union has filed a landmark lawsuit in order to push for equal marriage to be recognised in the US state of Pennsylvania.

Included in the plaintiffs for the case, filed in federal court in Harrisburg, are ten couples. The lead plaintiffs are Deb and Susan Whitewood.

The ACLU and the Philadelphia law firm Hangley Aronchick Segal Pudlin and Schiller, filed the complaint in the US District Court, in an effort to have the state’s Defense of Marriage Act deemed unconstitutional.

The act specifically defines marriage as between one man and one woman, and bars the state from recognising same-sex marriages, even those entered in other states.

“What we’re looking for is for the court to say: Here we are in the 21st century, and you cannot prohibit somebody from participating in this wonderful institution we call marriage,” said Witold Walczak, legal director of the Pennsylvania ACLU.

“We are expecting a trial in this case — a relatively short discovery period, and then a trial,” he said. “I don’t think Tom Corbett is going to lay down on this.”

This filing comes just two weeks after the Supreme Court struck down the federal Defense of Marriage Act, and the ACLU will cite that decision in its complaint, but did add that the decision to file it was not based on the Supreme Court ruling.

The Supreme Court ruling has little impact on same-sex couples living in the state.