The state's landmark gay marriage case applies only to Massachusetts residents and explicitly protects other states' rights to define marriage in their own way, according to a brief filed Monday by the attorney general.

A Suffolk County judge is scheduled to hear arguments Tuesday on a lawsuit filed by eight out-of-state gay couples who are seeking a preliminary injunction against a 1913 law that prohibits marriages that would be unlawful in a couple's home state.

Massachusetts Attorney General Thomas Reilly (search) argues the couples' complaint ignores specific references to other states in last year's state Supreme Judicial Court decision that allowed gay marriage (search).

Language throughout that decision "recognizes that other states are entitled to reach their own conclusions about same-sex marriage," Reilly wrote.

Michele Granda, attorney for Gay and Lesbian Advocates and Defenders (search), or GLAD, called Reilly's argument "creative," saying that the couples' case addresses the entire "marriage scheme," not just a specific claim.

"The bottom line is, we're looking at whether it's appropriate to be looking at the laws of some other states when someone comes to Massachusetts wanting a Massachusetts marriage license from a Massachusetts clerk," Granda said.

The Supreme Judicial Court ruled 4-3 in November it was unlawful under the state constitution to bar same-sex couples from marrying. The first gay marriages occurred in Massachusetts on May 17.