VA General Counsel Opinion 4-2014 (VAOPGCPREC 4-2014) addresses the definition of "spouse" and "surviving spouse" in Title 38 rules and regulations. Currently, Title 38 defines these terms only as persons of the opposite sex from the claimant (38 U.S.C. Sec. 101(3) and Sec. 31); however, President Obama's executive order requires the VA to cease enforcement of this definition. While the actual law did not change, the VA notes that the current provisions of Title 38 requires the the VA to recognize the laws of the place where the marriage took place as binding. So, for example, if the marriage took place in a state or jurisdiction where same sex marriage is legally recognized, the VA is automatically obliged to recognize the marriage regardless of gender orientation. This opinion then recognizes as "spouse" or "surviving spouse" the legally married partner regardless of sexual orientation if the marriage was legally valid in the place where the marriage took place. In other words, the marriage must "legally binding" by state law for VA to recognize the union under current rules.
Further, the VA took additional steps (VAOPGCPREC 3-2014) to use the provisions of 38 U.S.C. Sec. 5110(g) and 38 C.F.R. 3.113(a) to establish retroactive start dates for claims that would have been allowed under this new interpretation on the basis of "liberalizing legislation." This rule allows VA to establish a retroactive start date for a claim for a previously denied claim if the laws and policies of the VA are changed to the benefit of the claimant. In other words, claims denied because of the previous restrictions on the definition of "spouse" and "surviving spouse" may now be reopened and awarded (if all other eligibility criteria is met) retroactively to what would have been the original start date.
You can find the actual text of these important opinions here:
VAOPGCPREC 3-2014 ( Effective Dates on Awards Based on Same-Sex Marriage)
VAOPGCPREC 4-2014 (Reliance on State Law to Determine Validity of Same-Sex Marriage)