(Boston, Massachusetts) Fears are mounting that the Obama administration is about to flip-flop on its opposition to the Federal Defense of Marriage Act.

Last March, a federal lawsuit was filed in Boston challenging the law which bars the federal government from recognizing same-sex marriage.  The Justice Department has until June 22 to respond to the lawsuit.  So far there has been no comment from either the department or the White House.

The Department of Justice typically defends laws passed by Congress. But during the election campaign, then-candidate Obama pledged to overturn the ban.

A grassroots online campaign  called Equal Rep has begun to pressure the administration to keep his campaign promise by asking Attorney General Eric Holder “not to defend this unconstitutional law.” 365gay blogger Emma Ruby-Sachs helped craft the legal memo to Obama, which states in part, “The President reserves the right to refuse to defend an unconstitutional statute. Section 3 of the DOMA is clearly unconstitutional in that it denies married same-sex couples economic benefits granted to heterosexual married couples from the same state without providing a rational basis for this discrimination. ”

The Web site includes a cut-out mailer urging the president not to flip flop on the issue.

Support is slowly growing in Congress for repeal of the 1998 law, but a bill has yet to be filed in either the House or the Senate. In the meantime, the lawsuit challenging DOMA appears likely to proceed.

The lawsuit was filed by Gay & Lesbian Advocates & Defenders, the group that brought a successful legal challenge leading to Massachusetts becoming the first state in the nation to legalize gay marriage in 2004.  GLAD brought a similar successful suit in Connecticut.

GLAD represents eight married couples and three surviving spouses from Massachusetts who have been denied federal legal protections available to spouses. The lawsuit alleges that the act discriminates against gay couples and is unconstitutional because it denies them access to federal benefits that other married couples receive, such as pensions and health insurance. 

Among the plaintiffs is Dean Hara, the widower of former U.S. Rep. Gerry Studds, the first openly gay member of the House of Representatives.

Another plaintiff is Mary Ritchie, a Massachusetts State Police trooper who has been married for almost five years and has two children. But when she files her federal income tax return, she’s not allowed to check the “married filing jointly” box as a result of DOMA.

In Ritchie’s case, she and her spouse say they have paid nearly $15,000 more in taxes than they would have if they had been able to file joint returns.

The Defense of Marriage Act, or DOMA, was enacted by Congress in 1996 when it appeared Hawaii would soon legalize same-sex marriage and opponents worried that other states would be forced to recognize such marriages. 

The GLAD lawsuit challenges only the portion of the law that prevents the federal government from affording Social Security and other benefits to same-sex couples. 

Among those in Congress calling for repeal of the act is Sen. Tom Harkin (D-Iowa), one of the original supporters of the measure. Harkin said earlier this month that he has changed his mind on same-sex marriage.

”We all grow as we get older, we learn things, we become more sensitive to people and people’s lives,” Harkin told Iowa public television. ”The more I’ve looked at that, I’ve grown to think differently about how we should live. I guess I’ve got to the point of live and let live.”

Even if the bill is filed this session, it may find difficulty getting to a vote.  In addition to opposition from Republicans and number of conservative Democrats, mainly from Bible belt states Speaker Nancy Pelosi (D-Calif.) seems in no rush to advance repeal.

This month Pelosi suggested there may not be enough votes yet for repeal. 

In a recent Quinnipiac University public opinion poll, voters showed narrow support maintaining DOMA – 50-44 percent.