Colorado Democrats have been insisting that their ballot initiatives are not designed to overturn TABOR. They tell a very different story to friendly audiences such as the NEA when they don't realize they are going to be quoted. Here's our State Treasurer Cary Kennedy, quoted by Education Week, caught in a rare moment of frankness about the true goal of Amendment 59:

Colorado Speaker of the House Andrew Romanoff praised the NEA’s state chapter as one of the “most aggressive and successful” groups assisting Democrats in their takeover Colorado’s Statehouse and governor’s mansion. State Treasurer Cary Kennedy (no relation to RFK Jr.) said that Democrats would win a ballot initiative to “drive a stake in the heart” of the state’s Taxpayers Bill of Rights--a conservative cost-cutting measure.

There you have it straight from the source. There really isn't much more to add to that.