| Election Date | State | Title | Outcome |
|---|---|---|---|
| Nov. 4, 2008 | Colorado | Amendment 46: Discrimination and Preferential Treatment by the State | Failed |
| Nov. 8, 2016 | Colorado | Amendment T: No Exception to Involuntary Servitude Prohibition | Failed |
| Nov. 6, 2018 | Colorado | Amendment A: Prohibit Slavery and Involuntary Servitude in All Circumstances | Passed |
| Nov. 3, 2020 | Colorado | Amendment 76: Citizenship Qualification of Electors | Passed |