DHS Secretary Janet Napolitano has directed USCIS to “review immigration visa petitions filed on behalf of a same-sex spouse in the same manner as those filed on behalf of an opposite-sex spouse.”
If you are a U.S. Citizen or Lawful Permanent Resident, and you were lawfully married to a person of the same sex in a jurisdiction that legally recognizes same-sex marriage, then you may file and I-130 Petition to begin the green-card process for your same-sex spouse. USCIS will review your petition and will make a decision using the same procedures and rules that are used to review petitions filed for opposite-sex spouses.
If you and your same-sex spouse were lawfully married in a place that legally recognizes same-sex marriage, but you now live in a state that does not recognize same-sex marriage, USCIS will still review your petition. With very few exceptions, USCIS will look the law of the place where you married, and not to the law of the place where you are currently living, to determine whether your marriage is valid for purposes of immigration law.
Please note that, as with all marriage-based petitions, USCIS will review each petition to determine not only whether the marriage is legally valid, but also to determine the good-faith nature of the marriage. USCIS looks to the circumstances of the marriage relationship, including, but not limited to, issues such as whether the couple live together, share financial burdens and benefits, and have a history of being in communication with one another over time.
If you are considering filing a marriage-based petition, it is a good idea to consult with an immigration attorney in order to have the best chance of success and to avoid problems with the petition.