Colorado is asking the federal courts to stay out of a dispute about whether its strict tax and spending limits has robbed the state of a republican form of government.

In arguments Monday, state Solicitor General Daniel Domenico told a three-judge panel of the 10th U.S. Circuit Court of Appeals that lawmakers still have the ability to ask voters to approve a tax increase if they think one is needed under the Taxpayer's Bill of Rights.

"Just because it's a little bit harder doesn't make it unrepublican," he said of the referendum needed to raise taxes under TABOR.

Domenico said that if lawmakers tried and failed to win a tax increase, they might have a case. But he also argued that courts haven't gotten involved in enforcing the provision in the U.S. Constitution guaranteeing a republic — or representative democracy — to the states, leaving that to Congress instead.