Colorado voters have an unusual ballot measure awaiting them this fall — whether to make it harder to change the state constitution through a ballot measure.

A measure approved for state ballots Tuesday would require constitutional amendments to pass by 55 percent, not 50 percent. The proposal would also make it harder to gather the voter signatures required to put amendments on the ballot, raising it from about 98,000 signatures to 2 percent of the registered voters in each of the state’s 35 state Senate districts.

The “Raise The Bar” campaign has supporters from both parties who complain that Colorado’s state constitution is too easy to change. But Colorado voters have twice before rejected proposals to make it harder to change the state constitution, in 2008 and in 1996.