Under the Supreme Court decision of United States v. Windsor, Section 3 of DOMA was declared unconstitutional, and as a result the Federal government is required to recognize same-sex marriages that are recognized by the state. However, in Hollinsworth v. Perry the Supreme Court simply ruled that the appellants did not have standing to defend California's Proposition 8 same-sex marriage ban; the court did not actually rule on the legitimacy of Proposition 8 itself, and thus did not address whether Section 2 of DOMA – which exonerates states from any obligation to recognize same-sex marriages – is Constitutional.
As a result, while the Federal government must recognize state-sanctioned same-sex marriages, it is not the case under current law that all states must allow same-sex marriages, nor even that all states must recognize same-sex marriages that originated in other states. Instead, for the time being, the matter remains entirely a state-by-state issue, until/unless a new legal dispute comes forth that specifically challenges Section 2 of DOMA, and/or Congress otherwise repeals or alters the remaining provisions of DOMA.
However, this current state of affairs creates significant challenges for same-sex couples who marry in a state that recognizes the marriage, but later relocate to a state that does not. Under Federal law, the treatment of such situations varies, depending on whether the Federal provisions look to the "state of residence" to determine marital status, or the "place of celebration" - and currently, some Federal programs adopt one definition, while some utilize the other. Thus, for the time being, financial planners will need to be cognizant of which status applies to a client, which rules apply to a client, and stay alert as the definitions are anticipated to change in the coming months at Federal agencies and programs seek to refine their rules and regulations for determining marital status in light of the Supreme Court decision.