On Thursday, a three-judge panel for the 1st U.S. Circuit Court of Appeals in Boston ruled that the Defense of Marriage Act (DOMA) — which defines marriage as being between a man and a woman —  is unconstitutional. This marks the first time that a federal appeals court has struck down the law, making it likely that the constitutionality of DOMA will eventually be weighed by the Supreme Court. Here, five takeaways from the landmark decision:

1. The court didn't declare gay marriage a constitutional right
The court focused on a provision in DOMA that denies federal benefits — such as the ability to file taxes jointly or receive Social Security survivor benefits — to married same-sex couples. The court said that part of the law is unconstitutional because it interferes with the right of states to craft their own marriage laws by discriminating against same-sex couples in states where gay marriage is legal. The court stopped short of ruling that gay couples have a constitutional right to marry, nor did it force all states to recognize the legality of same-sex marriages performed in states where it is legal.

2. Two GOP-appointed judges joined the ruling 
The three-judge panel, which included two Republican-appointed judges, was unanimous in its decision, strengthening the nonpartisan case against DOMA. Judge Michael Boudin was appointed by George H.W. Bush, while Judge Juan Torruella was appointed by Ronald Reagan. The third judge, Sandra Lynch, was appointed by Bill Clinton, who signed DOMA into law in 1996.

3. The Obama administration did not defend the law 
While it's customary for the Justice Department to defend challenges to all federal laws, the Obama administration announced last year that it would not defend DOMA in court, deeming it unconstitutional. Obama only recently became the first sitting president to endorse gay marriage, though he says the definition of marriage should be left to the states. 

4. DOMA opponents are claiming a huge victory
"Today's landmark ruling makes clear once again that DOMA is a discriminatory law for which there is no justification," says Massachusetts Attorney General Martha Coakley. "It is unconstitutional for the federal government to create a system of first- and second-class marriages." 

5. But the ruling will not go into effect... yet 
The Boston court said its ruling would have no effect on DOMA in practice, affirming that "only the Supreme Court can finally decide this unique case." The latest ruling followed a similar decision by a district judge in California last week, "a further chipping away at the law that is almost certain to see it land before the Supreme Court within the next year or so," says Chris McGreal at Britain's The Guardian.

Sources: Associated PressThe Boston Globe, The GuardianThe Washington Post