The 2nd Circuit broke new legal ground by saying that laws discriminating against gays, like those targeting racial minorities and women, should get especially rigorous scrutiny from the courts. The Obama administration backs that approach.
The court will review the law using the case of 83-year-old New York resident Edie Windsor, who is fighting a $363,000 estate tax bill imposed after the 2009 death of her spouse, Thea Clara Spyer. Windsor and Spyer were married in Canada in 2007, a marriage the 2nd Circuit concluded would be recognized under New York law.
The legal battle over DOMA doesn't affect a separate provision in the law that says states can refuse to recognize same-sex marriages from other jurisdictions.
Kennedy looms as the potential swing vote in both cases. He has been a champion of gay rights in past cases, writing the 2003 decision that said states can't criminalize gay sex acts. Overturning the convictions of two men in Texas, he wrote that "the state cannot demean their existence or control their destiny by making their private sexual conduct a crime."
Kennedy, appointed by President Ronald Reagan in 1988, also wrote the court's 1996 decision striking down a Colorado constitutional amendment that barred cities and counties from enacting anti-discrimination laws to protect gays.
Even so, he underscored in 2003 that he wasn't passing judgment on gay marriage. He said the case "does not involve whether the government must give formal recognition to any relationship that homosexual persons seek to enter."
With assistance from Esme E. Deprez in New York.