U.S. state constitutional amendments banning same-sex unions States that have voted on amendments States that have voted on amendments

| State_ | Date_ | Yes_vote | No_vote | Vote_outcome |
|---|---|---|---|---|
| Missouri | 2004 | 71% (1,055,771) | 29% (439,529) | Yes |
| Michigan | 2004 | 59% (2,698,077) | 41% (1,904,319) | Yes |
| North Dakota | 2004 | 73% (223,572) | 27% (81,716) | Yes |
| Ohio | 2004 | 62% (3,329,335) | 38% (2,065,462) | Yes |
| Oklahoma | 2004 | 76% (1,075,216) | 24% (347,303) | Yes |
| Kansas | 2005 | 70% (414,106) | 30% (178,018) | Yes |
| South Dakota | 2006 | 52% (172,242) | 48% (160,173) | Yes |
| Wisconsin | 2006 | 59% (1,260,554) | 41% (861,554) | Yes |
| Minnesota | 2012 | 47% (1,399,938) | 53% (1,550,844) | No |
| South: | South: | South: | South: | South: |
| Louisiana | 2004 | 78% (618,928) | 22% (177,103) | Yes |
| Arkansas | 2004 | 75% (753,770) | 25% (251,914) | Yes |
| Georgia | 2004 | 76% (2,454,912) | 24% (768,703) | Yes |
| Kentucky | 2004 | 75% (1,222,125) | 25% (417,097) | Yes |
| Mississippi | 2004 | 86% (957,104) | 14% (155,648) | Yes |