Kly, I think the Court could base it's DOMA decision on Article IV: Full faith and credit. What do you think?
I'd be a little disappointed if the Court limited its analysis to the Full Faith and Credit Clause. Certainly there are unresolved issues of the application of Article IV to the issue of gay marriage, which need to be addressed. While it certainly applies to man/woman marriages without equivocation, courts have not required states that oppose gay marriage to recognize same sex marriages performed in other states.
Limiting the decision on Article IV grounds would allow the Court to avoid making a sweeping determination on Fourteenth Amendment grounds, and would let the thirty-something states that passed state constitutional amendments and legislation forbidding gay marriage keep their provisions intact.
One of the pending matters involves a woman, who married her female companion legally before the companion died. As a result, under DOMA she was not recognized as a spouse and had to pay inheritance tax of more than $300,000 in estate taxes where, had her companion been a husband, she would not have had to pay any tax at all. This scenario, I believe, calls for equal protection analysis.
Another reason the Court might decide the case narrowly on Article IV, I think, is that it might be unwilling to define a standard of review for gay rights cases. Some feel that strict scrutiny, which is used for reviewing cases that involve racial issues or fundamental rights should apply while others might feel that intermediate scrutiny, which is applied in gender cases, should apply.
The Court historically doesn't like to take leaps, so if these cases result in a constitutional right for same sex marriage at this time, it would represent an event similar to Brown.