Every state but Delaware requires voters to ratify proposed changes to a state’s constitution.

There are four ways that proposed constitutional amendments can be proposed and put on the ballot:

• Through legislatively referred constitutional amendments.
• Through citizen-initiated constitutional amendments put on the ballot through signature petition drives. Eighteen states allow this method of amendment.
• Through referral by constitutional conventions. In some states, automatic ballot referrals allow voters to decide at regular intervals whether or not to hold a convention.
• In Florida, there is a commission-referred amendment process through the Constitution Revision Commission that meets every 20 years. It last met in 2018.

From 2006 through 2020 a total of 1,016 constitutional amendments were proposed and put before voters. This data only includes constitutional amendments put on the ballot for a statewide vote. It does not include certain state constitutional amendments that only apply to local jurisdictions and were voted on only by residents of particular local jurisdictions. It also does not include constitutional amendments in Delaware that weren’t subject to voter ratification. Of this total, voters approved 733 proposed changes to state constitutions.

In 2020, voters in 29 states decided a total of 84 constitutional amendments. Of the 84 proposed amendments, state legislatures referred 69 to the ballot, and signature petition drives were used to initiate the other 15. Of the 84 amendments, 62 (73.8%) were approved.

Since 2006, the even-numbered year with the most proposed amendments on the ballot was 2006 with 148, and the year with the least amount of proposals was 2020, which had 84 proposals. The average in even-numbered years since 2006 was 109.

Among states with a process for initiated constitutional amendments, Florida and Colorado featured the most proposed constitutional amendments on the ballot from 2006 through 2020, with a total of 56 and 52, respectively. Of that total, Florida voters approved 37, and Colorado voters approved 21. Among all 50 states, Louisiana featured the most proposed constitutional amendments and the most approved amendments.

States featured an average of 20 constitutional amendments on the ballot from 2006 through 2020. Across all states, an average of 15 amendments were approved. Statistically, from 2006 through 2020, off-year election cycles featured a higher approval rate for proposed constitutional amendments than even years. In 2007, 28 of the 31 proposed amendments were approved, for a rate of 90%. In 2013, amendments passed at a rate of 89%. In 2017, all 17 amendments on the ballot were approved, for the highest approval rate since 1947. In contrast, 2006 and 2020 had the highest approval rates of even-numbered years since 2006 at 74.5%and 73.8%, respectively.