The Defense of Marriage Act (1996) was a federal law that defined marriage as opposite-sex for federal purposes and let states refuse to recognize same-sex marriages from other states. The Supreme Court struck down its core in United States v. Windsor (2013), and Obergefell v. Hodges (2015) finished the job.
The Defense of Marriage Act (DOMA) was a 1996 federal statute with two big moves. First, it defined marriage as between one man and one woman for all federal purposes, so legally married same-sex couples were locked out of over a thousand federal benefits like joint tax filing and Social Security survivor benefits. Second, it told states they did not have to recognize same-sex marriages performed in other states, carving an exception into Article IV's Full Faith and Credit Clause, which normally requires states to honor each other's legal acts.
For AP Gov, DOMA is less about marriage and more about federalism in action. Marriage law has always been a state power, so when Congress stepped in with a national definition, it created a direct national-versus-state collision. The Supreme Court invalidated the federal definition in United States v. Windsor (2013), partly on the logic that defining marriage belongs to the states, and then Obergefell v. Hodges (2015) required all states to license and recognize same-sex marriages under the Fourteenth Amendment, making DOMA's state-recognition provision dead too.
DOMA lives in Topic 1.9, Federalism in Action, inside Unit 1 (Foundations of American Democracy). It directly supports learning objective AP Gov 1.9.A, which asks you to explain how the distribution of powers between national and state governments impacts policymaking. DOMA is a near-perfect case study. The CED's essential knowledge says federalism creates multiple access points for stakeholders to influence policy, and the same-sex marriage fight shows every single one. Advocates won in some state legislatures and state courts, opponents responded with state constitutional amendments and a federal statute, and the final word came from the federal judiciary. That is what 'multiple access points' looks like in real life. DOMA also shows the other half of the essential knowledge, that national policymaking is constrained by concurrent powers, because Congress tried to nationalize a traditionally state-controlled area and the Court pushed back.
Keep studying AP® Gov Unit 1
Dual Federalism (Unit 1)
Dual federalism imagines clean, separate layers where states own family law and the national government stays out. DOMA blurred that line on purpose, and Windsor partly redrew it by saying marriage definitions belong to the states. DOMA is your evidence that the 'layer cake' boundaries get contested constantly.
Cooperative Federalism (Unit 1)
Most cooperative federalism examples involve money and grants, but DOMA shows national-state entanglement without a dollar attached. Federal benefits like taxes and Social Security depend on a marital status that states define, so the two levels are tangled together whether they cooperate or not.
Equal Protection and Obergefell v. Hodges (Unit 3)
DOMA is where Unit 1 federalism and Unit 3 civil rights collide. Windsor used Fifth Amendment equal protection logic against the federal government, and Obergefell used the Fourteenth Amendment against the states. If an FRQ asks how constitutional provisions expanded civil rights, the DOMA-to-Obergefell arc is a ready-made answer.
Commerce Clause (Unit 1)
Both DOMA and Commerce Clause cases like United States v. Lopez raise the same question from different angles. Where does national power end and state power begin? Lopez tests it through economic regulation, DOMA tests it through family law. Knowing both gives you two distinct examples for any federalism prompt.
DOMA usually shows up as a real-world illustration rather than a term you define in isolation. Multiple-choice stems may give you a scenario (Congress passes a law in an area traditionally regulated by states) and ask which federalism principle is at stake, or pair DOMA with Windsor or Obergefell and ask what changed. On FRQs, DOMA is strong supporting evidence for the Concept Application question or an Argument Essay about federalism, because you can show power moving between levels of government over time. No released FRQ has required DOMA by name, but a federalism argument that traces state marriage laws, then DOMA, then Windsor and Obergefell demonstrates exactly the kind of specific, accurate evidence the rubric rewards. The key skill is connecting it to LO 1.9.A language, meaning multiple access points and constraints on national policymaking.
Students constantly merge these two cases, and the difference matters for points. Windsor (2013) struck down DOMA's federal definition of marriage, so the federal government had to recognize same-sex marriages that states had already legalized. It did not force any state to allow them. Obergefell (2015) went further and required every state to license and recognize same-sex marriages under the Fourteenth Amendment. Short version: Windsor killed DOMA, Obergefell legalized same-sex marriage nationwide.
DOMA was a 1996 federal law that defined marriage as opposite-sex for federal purposes and allowed states to refuse recognition of same-sex marriages from other states.
It is the AP Gov go-to example for federalism conflict, because marriage law is traditionally a state power and Congress tried to set a national rule anyway.
United States v. Windsor (2013) struck down DOMA's federal definition of marriage, and Obergefell v. Hodges (2015) made same-sex marriage legal in every state.
DOMA's state-recognition provision carved into Article IV's Full Faith and Credit Clause, which normally makes states honor each other's legal acts.
The same-sex marriage fight proves the CED's point that federalism creates multiple access points, since advocates won through state legislatures, state courts, and finally the federal judiciary.
Use DOMA on FRQs to show that national policymaking is constrained by concurrent and reserved state powers, the core of LO 1.9.A.
DOMA is a 1996 federal law that defined marriage as one man and one woman for federal purposes and let states refuse to recognize same-sex marriages from other states. In AP Gov it appears in Topic 1.9 as an example of national-state conflict over policymaking power.
No. The Supreme Court struck down the federal definition of marriage in United States v. Windsor (2013), and Obergefell v. Hodges (2015) required all states to license and recognize same-sex marriages, leaving DOMA fully unenforceable. Congress also formally replaced it with the Respect for Marriage Act in 2022, though that goes beyond what the AP exam requires.
No, and this is the trap. Windsor (2013) only struck down DOMA's federal definition, forcing the federal government to recognize marriages that states had already legalized. Nationwide legalization came two years later with Obergefell v. Hodges (2015).
DOMA shows the national government reaching into marriage law, an area traditionally reserved to the states, which triggers exactly the tension LO 1.9.A asks about. It also illustrates multiple access points, since the policy battle ran through state legislatures, state courts, Congress, and the Supreme Court.
Article IV's Full Faith and Credit Clause generally requires states to honor other states' public acts and records, including marriages. DOMA created an exception by authorizing states to ignore same-sex marriages performed elsewhere, which is why it raised constitutional questions from the start.
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