The Electoral College system is established in the Constitution. When voters cast a ballot for president, they are actually choosing members of the Electoral College, called electors, who are pledged to that presidential candidate. The electors then choose the president.
Electors almost always vote for the popular vote winner, and some states have laws requiring them to do so.
But the split decision by a three-judge panel on the Denver appeals court said the Constitution allows electors to cast their votes at their own discretion. “The state does not possess countervailing authority to remove an elector and to cancel his vote in response to the exercise of that Constitutional right,” the ruling said.