Colo. Const. art. X, § 16

Appropriations not to exceed tax - exceptions. No appropriation shall be made, nor any expenditure authorized by the general assembly, whereby the expenditure of the state, during any fiscal year, shall exceed the total tax then provided for by law and applicable for such appropriation or expenditure, unless the general assembly making such appropriation shall provide for levying a sufficient tax, not exceeding the rates allowed in section eleven of this article, to pay such appropriation or expenditure within such fiscal year. This provision shall not apply to appropriations or expenditures to suppress insurrection, defend the state, or assist in defending the United States in time of war.