New York’s law granting marriage rights to same-sex couples has only been in effect for a week, but advocates on both sides of the issue have wasted no time taking their arguments to court.

Attorney General Eric Schneiderman has filed court papers charging that the federal Defense of Marriage Act (DOMA), which defines marriage as being between a man and a woman, is unconstitutional on a number of fronts, including an “unprecedented intrusion” on the right of states to regulate marriage.

DOMA, passed in 1996, has been under heightened scrutiny since the Obama administration announced in February that it would no longer uphold the part of the law that bars the federal government from recognizing legal same-sex marriages.

According to the General Accounting Office, married same-sex couples do not receive more than 1,100 federal rights extended to straight couples. These include an exemption from estate taxes when a spouse dies, social security and veterans benefits, and the options to file joint federal income tax returns and bankruptcy petitions, among others.

In a brief filed in the case Windsor v United States of America, Schneiderman argued that DOMA violates the Fifth Amendment by failing to provide equal rights to all Americans and the Tenth Amendment by impeding the right of states to regulate marriage.

He also says DOMA blocks New York and other states from extending full equality to same-sex couples.

“Without such equal treatment by the federal government, New York’s statutory commitment to marriage equality for all married couples will be substantially unrealized,” Schneiderman wrote in the brief.

The Windsor case was brought by a New York woman, Edie Windsor, who was hit with a substantial estate tax after her partner of 44 years died in 2009. The women had been married in Canada in 2007. Under federal law, widowed spouses in heterosexual marriages can inherit money and other assets without facing the tax.

Meanwhile, conservative Christian lobbying group New Yorkers for Constitutional Freedoms has filed a lawsuit against the state Senate, essentially alleging that gay marriage supporters thwarted democracy by bending legislative rules and promising big campaign contributions to Republican lawmakers who supported the measure.

“It is unfortunate that state senators chose to protect their personal interests, rather than the people they were elected to represent,” said the head of the group, the Rev. Jason McGuire.

The suit also claims that Gov. Andrew Cuomo should not have issued a “message of necessity” that allowed lawmakers to waive the required three-day waiting period between a bill’s introduction and a vote.

Senate officials are not commenting on the suit, and a spokesman for Cuomo said the charges are “without merit.”

Sen. Greg Ball, a Putnam County Republican who voted against the marriage bill because it did not include enough protections for religious objectors, defended his colleagues.

“This group apparently would have liked to see old Albany rear its ugly head, where a small minority controlled by the extreme and petty interests could have killed democratic action,” Ball said. “Rarely has democracy been as active or alive as it was the day of that vote.”