The Obama administration on Friday filed a brief in federal court that said the Defense of Marriage Act (DOMA) is unconstitutional. The 1996 law bars federal agencies from recognizing the legal marriages of gay and lesbian couples.

Karen Golinski, a 9th U.S. Circuit of Appeals lawyer, sued the government after her employer denied health insurance coverage to her wife, Amy Cunninghis. The U.S. Office of Personnel (OPM) argues that DOMA blocks such benefits.

In its brief, however, the Justice Department, which announced earlier it would no longer defend the law in court, sided with Golinski.

“The official legislative record makes plain that DOMA Section 3 was motivated in large part by animus toward gay and lesbian individuals and their intimate relationships, and Congress identified no other interest that is materially advanced by Section 3,” the DOJ wrote.

Speaking to the Associated Press, Tobias Barrington Wolff, a law professor at the University of Pennsylvania, called the brief a “complete paradigm shift.”

“This brief represents the concrete manifestation of a complete paradigm shift in the federal government's position on anti-gay discrimination and the constitutional rights of married same-sex couples,” Wolff said.

Joe Solmonese, president of the Human Rights Campaign, the nation's largest gay rights advocate, cheered the government's filing.

“The Administration's decision to call DOMA what it is – a law that serves no purpose but to single out a group of people for second-class status – was a watershed moment in the fight for LGBT equality. Now the federal government has taken that historic stand a step further and put real meat on the bones of why there is no basis for DOMA to stand. This step represents real leadership from the Obama administration and further hastens the day in which we will leave this odious law in the dustbin of history.”

In its 31-page filing, the agency argued that sexual orientation is an “immutable characteristic” and that DOMA serves no legitimate policy interest.

“It's quite powerful to have the administration saying in a court filing that this kind of discrimination should be viewed suspiciously,” Golinski's attorney Tara Borelli said.

Attorneys hired by the U.S. House of Representatives had asked the court to dismiss the case.