The Obama administration says it will not defend the federal ban on gay marriage in court, but tax season could force the issue.
Jezebel points us to an organization called Refuse to Lie, which is advocates that married gay couples (whose marriages are recognized under state law, but not, as the Defense of Marriage Act still stands, under federal law) file as single, yet attach this disclaimer:
Sample Attachment to Federal Tax Return Affirming Marriage
Name of taxpayer:
Social Security #:
The above named taxpayer married a person of his/her same sex in [place] in [year]. The taxpayer has not filed this return as "married" (either jointly or separately) solely because the Defense of Marriage Act (DOMA) defines marriage as a legal union between a man and a woman. By filing as "single," the taxpayer is in no way disavowing his/her marriage.
If you want a sense of how essentially and legally complicated this issue is, the whole Refuse to Lie tax-preparation memo is worth a read. It's generally not a good idea to lie to the IRS; if you're married, you have to tell them so.
Consequently, the group also recommends suing the federal government:
File two single returns (including the attachment affirming the marriage) and then file an amended return, filing jointly. The amended return is a 1040X. This is what the plaintiffs in the GLAD case did. Once the IRS rejects the amended return, or if six months passes and they do nothing, the taxpayers who file an amended return have the right to file suit in federal district court claiming the refund.
The basis of the claim for refund by a Florida same-sex couple would be that they were married, that under the U.S. Constitution that marriage should be recognized, that it would be perjury to claim otherwise, and that DOMA itself is unconstitutional. This option would avoid penalties because your original return would be filed according to the statute.
Gay & Lesbian Advocates & Defenders (GLAD) is currently challenging the DOMA law.