The 2nd U.S. Circuit Court of Appeals on Thursday because the second federal appeals court to find parts of the so-called Defense of Marriage Act (DOMA) to be unconstitutional.

A three-judge panel in Manhattan ruled that Section 3 of DOMA violated the equal protection clause of the U.S. Constitution.

The American Civil Liberties Union (ACLU) had challenged the law on behalf of Edith “Edie” Windsor, who had to pay $363,000 in federal estate taxes after the 2009 death of her partner, Thea Spyer, even though the couple had been recognized as legally married in New York.

"DOMA’s classification of same-sex spouses was not substantially related to an important government interest," Chief Judge Dennis Jacobs and Judge Christopher Droney wrote in their majority opinion. “Accordingly, we hold that Section 3 of DOMA violates equal protection and is therefore unconstitutional.”

In a statement provided to Raw Story by the ACLU, Windsor praised the decision.

"This law violated the fundamental American principle of fairness that we all cherish," Windsor said. “I know Thea would have been so proud to see how far we have come in our fight to be treated with dignity.”

Windsor's DOMA case is one of several that are pending consideration by the United States Supreme Court. The high court has not said if it would take up the case.