This November, Proposition CC will ask Colorado voters to permanently lift the spending limits in the Taxpayer’s Bill of Rights, but the political stakes embedded in the question are even more consequential. The ballot question represents the most significant overhaul to TABOR since voters approved the constitutional provision in 1992, and serves as a test case for a broader Democratic effort to overhaul how the state levies taxes and spends money. If voters approve Prop. CC, Democratic leaders and their allies believe it would give them momentum for a broader agenda to revamp property tax rates, increase taxes for key...