The court may determine the constitutionality of California's Proposition 8 measure that limits marriage to one man and one woman.
There could also be a decision regarding whether part of the federal "Defense of Marriage Act" is unconstitutional because it denies benefits to legally married same sex couples.
"It seems to me that the court will find some way of ruling without actually deciding the big question for the entire country one way or the other," said Carolyn Shapiro, Chicago-Kent's Institute.
"The court probably will overturn the defense of marriage act and will probably nix in part the Proposition 8," said Tom Thayer, Gay Liberation Network. "The problem with that is they're talking perhaps about a one state solution in terms of marriage equality in California only."
In Illinois, the gay marriage bill passed the senate but no action has been taken in the house.
Lawmakers say they plan to call the legislation for a vote during the next session.