the city and county of denver has always been liberal but there were enough conservatives in the burbs to keep them in the looney minority. In statewide and national races Colorado was reliably conservative until 10-15 years ago. Even the deepest red states have their pockets or loons. As long as they remain in the minority they can do little harm
Since 1975 there has only been ONE Republican governor of Colorado, and that was Bill Owens (1999-2007). Sounds like Colorado has been pretty much a Democrat state for almost 50 years. It’s a shame, because it was a beautiful state, physically (though I much prefer Wyoming and Montana).