WASHINGTON — Three members of Maine’s congressional delegation have added their voices to those urging the U.S. Supreme Court to overturn the federal Defense of Marriage Act.

U.S. Sen. Angus King, I-Maine, and the state’s two U.S. House members, Democrats Chellie Pingree and Mike Michaud, announced Friday in a joint statement that they are among 212 members of Congress filing an amicus brief in U.S. v. Edith Schlain Windsor, a case that challenges the constitutionality of the 1996 Defense of Marriage Act, which defines marriage for purposes of federal law as “only a legal union between one man and one woman.”

The fourth member of Maine’s congressional delegation, Republican Sen. Susan Collins, did not sign the brief. No Republican did.

“It’s neither fair nor right that married same-sex couples are denied equal access to the same federal benefits that all other married couples enjoy,” King said Friday in an email to the Bangor Daily News. “That’s why I joined with over 200 members of Congress today to not only convey my opposition to DOMA, but to also express my belief that everyone — regardless of who they are or where they live — deserves equal treatment under the law.”

The brief that King, Michaud and Pingree signed includes the names of 172 House members and 40 senators, all Democrats and independents. It states, in part, “DOMA imposes a sweeping and unjustifiable federal disability on married same-sex couples. … Our national security is undermined by denying spousal benefits to gay and lesbian service members, especially during periods of armed conflict. Our veterans are dishonored when we deny them the right to have their spouses buried alongside them in our national cemeteries.”

Collins reinforced her reputation as a rare moderate Republican in Congress by playing a lead role in ending the Pentagon’s “don’t ask, don’t tell” policy toward gay people serving in the U.S. military.

Collins also was the sole Republican Senate co-sponsor of the Domestic Partnership Benefits and Obligations Act, a bill to extend health insurance benefits to federal employees in same-sex relationships — legislation made necessary by Section 3 of the Defense of Marriage Act, which is the specific part of the bill targeted by the brief filed Friday by the 212 members of Congress.

“Recognizing that [lesbian, gay, bisexual and transgender] Americans should be protected from discrimination, Sen. Collins has led efforts in Congress to extend federal benefits to gay men and women and their families,” Kevin Kelley, a spokesman for Collins, said Friday in an email.

In 2004 and 2006, Collins opposed proposals to amend the U.S. Constitution to define marriage as a union between one man and one woman. Those changes would have effectively pre-empted state laws.

She believes the “issue of same-sex marriage is best addressed by the individual states,” Kelley wrote.

President Bill Clinton signed the act in 1996, before any member of Maine’s delegation was elected to Congress. The Supreme Court is scheduled to hear arguments in the case on March 27.

Maine Attorney General Janet Mills announced Thursday that she will join attorneys general from other states in a similar filing that urges the high court to strike down the Defense of Marriage Act. A coalition of more than 300 business groups also has submitted briefs arguing that the act should be deemed unconstitutional. President Barack Obama’s administration has told the Justice Department not to enforce DOMA and submitted a brief urging the Supreme Court to overturn California’s Proposition 8, which also bans same-sex marriage in that state.

“The administration’s complex legal brief calls for the invalidation of California’s ban on same-sex marriages which has implications for several other states, but the brief curiously does not challenge the prohibition on same-sex marriages in some 30 states that do not recognize domestic partnerships,” Kelley wrote in his email. “Sen. Collins will carefully follow the Supreme Court’s consideration of this important case.”

Maine voters legalized same-sex marriage by referendum in November 2012. Regardless of how the Supreme Court rules on the Defense of Marriage Act challenge, the state law will remain in effect, Mills said in December.