"This report provides an overview of the federal tax treatment of same-sex married couples, with a focus on the federal income tax. Estate tax issues are also discussed. The administration of federal tax laws for married same-sex couples changed as a result of the U.S. Supreme Court ruling in 'United States v. Windsor' in 2013, striking down Section 3 of the Defense of Marriage Act. The administration of federal tax laws was not affected by the June 26, 2015, ruling in 'Obergefell v. Hodges'. 'Obergefell' struck down state bans on same-sex marriage, holding that all states must both permit same-sex couples to marry in their states and recognize same-sex marriages that were formed in other states. While it did not change the administration of federal income tax laws, the 'Obergefell' decision may affect the number of same-sex couples who decide to marry (and hence the number of federal and state tax returns filed by married couples). Analysis of changes to individuals' state tax liabilities resulting from the 'Obergefell' decision is beyond the scope of this report; however, state tax changes may ultimately affect federal tax liabilities for those couples who itemize deductions on their federal returns. This report focuses on changes in the 'interpretation and administration' of federal tax law resulting from the Court's 'Windsor' decision. The decision itself did not amend federal tax law. This report is not intended to address all tax-related issues that may arise as a result of the federal recognition of same-sex marriages for tax purposes. Such discussion is beyond the scope of this report."
CRS Report for Congress, R43157