The decade-long legal attempt to declare Colorado’s Taxpayer Bill of Rights unconstitutional has come to an end, as the plaintiffs will let stand a decision from the U.S. Court of Appeals for the 10th Circuit that dismissed the case in December.

“The lawyers representing the plaintiffs have decided not to seek Supreme Court review of the 10th Circuit decision. So the case is over for now,” C.L. Harmer, a spokesperson for the plaintiffs, told Colorado Politics.

Although Harmer did not say whether the attorneys plan to refile the lawsuit in federal district court in some form, there have been no additional filings in the case since the 10th Circuit’s dismissal.

The lawsuit to overturn the 1992 TABOR amendment to Colorado’s constitution began in 2011 and encompassed a lengthy roster of plaintiffs, including state and local lawmakers, school districts, and a board of county commissioners. The theory behind the litigation was that TABOR, which mandates that new taxes or tax increases be put to a vote of the people, violated the 1875 law that made Colorado a state and guaranteed that its government be “republican in form.”

A “republican” form of government, the plaintiffs argued, requires that elected lawmakers be able to make taxing and spending decisions.

The lawsuit reached the 10th Circuit on multiple occasions, and even the Supreme Court. Finally, after a rare all-judges hearing at the 10th Circuit last year, the appeals court voted by 7-2 to dismiss the case in December. The majority concluded that the plaintiffs – at that point consisting entirely of the local government bodies – had not shown that the guarantee of a republican form of government applied to them.

“The clause promising a constitution republican in form has no clear beneficiary,” wrote Chief Judge Timothy M. Tymkovich.

Although TABOR was intended to restrain the growth of government, critics hold it responsible for Colorado’s low levels of investment in key government obligations, including education. Nevertheless, statewide attempts to permanently undo TABOR have stalled. In addition to the lawsuit, a 2019 ballot initiative seeking to redirect taxpayer refunds under TABOR to education and transportation failed to pass.

Another proposed initiative to repeal TABOR outright did not make it onto the ballot the following year.