Edith Windsor, the lesbian widow challenging the constitutionality of the Defense of Marriage Act (DOMA), on Tuesday urged the Supreme Court to strike down the law.

Windsor sued the federal government after she received an estate bill of more than $360,000 resulting from the death of her wife Thea Spyer.

The women shared their lives for 44 years and married in Toronto, Canada in 2007. In 2009, New York began recognizing the marriages of gay couples, although the state did not legalize such unions until 2011. Spyer died in 2009.

Quoting from opinions written by Justice Anthony Kennedy, considered a likely key vote in the case, lawyers for Windsor wrote: “As this court has already recognized, laws burdening lesbians and gay men that were 'once thought necessary and proper' may in fact 'serve only to oppress.'”

“[G]ay couples like Ms. Windsor and Dr. [Thea] Spyer marry for the same reasons straight couples do – to express their love and commitment to each other.”

The brief refutes arguments made by the House Bipartisan Legal Advisory Group (BLAG), the legal team defending the law in court. Specifically, that gay men and lesbians as a group are politically powerful and not in need of the court's protection.

“The fact that gay couples are the only legally married couples in the entire nation who cannot benefit from the wide range of federal benefits provided to all other legally married couples is itself powerful evidence of gay people's ongoing political vulnerability,” the Windsor brief states.

Oral arguments in the case are scheduled to be heard on March 17, and the court is expected to rule on the case by June.