If there's one thing both Democrats and Republicans in Colorado can agree on, it's that it's all too easy for citizens to change the state constitution. Now it looks like the amendment process could become harder.

A bipartisan civic group renewed their effort on Tuesday by filing ballot measures to make it more difficult to change the Colorado constitution. These measures would require ballot petition signatures collected from throughout the state and would raise the threshold for changing the constitution from a simple voter majority to 55%. Voters would have to approve the changes.

While marijuana legalization and the Taxpayers' Bill of Rights are among the amendments placed in Colorado's constitution by voters, the group did not call out any constitutional amendments it opposes.