Lynn Bartels has the lead story in today's Denver Post, noting that Colorado Governor John Hickenlooper's (D) longstanding and tightly-managed image as a moderate is crumbling, just as his reelection campaign is beginning in earnest. The piece has lots of good quotes from Colorado politicos on both sides, speculating on whether Hickenlooper has changed or had previously misrepresented himself. But they key thing to take away from this is that the context of a state's political environment has a huge impact on how we perceive its leaders.
Prior to his political career, Hickenlooper was a restauranteur, a microbrewer, and a geologist in the energy industry. That's already a pretty atypical biography for a Democratic politician, giving him some moderate bona fides. Then he served two terms as mayor of Denver -- a nonpartisan position.
The governor's office was his first official position as a Democrat. This position would theoretically force him into some partisan behavior, requiring him to take some stances to satisfy primary constituencies and to deliver on those stances once in office. But three things protected him. First, he faced no challenger for the Democratic nomination back in 2010. Second, the Republican Party imploded when trying to select his opponent that year, allowing him to win in a walk, meaning he didn't really owe anyone in his party anything. Third, during the first half of his term as governor, control of the legislature was split, with Democrats controlling the Senate and Republicans running the House. The only legislation that would reach his desk was already, by definition, bipartisan.
In 2012, however, Colorado joined a record 43 other states in placing both state legislative chambers under control of one party. Now very different legislation is coming across the governor's desk: gun control bills, renewable energy measures, civil unions, and so on. Once it's there, he has a choice of signing it into law or vetoing the clear preferences of his party and the state's voters, and the latter really isn't much of an option. Now, it's not like the governor has no say in which bills get considered -- he had previously signaled that he would be okay with such legislation -- but none of these bills would have come out of a split-controlled legislature. They're very much a product of the political environment.
So, to some degree, calling Hickenlooper a closet liberal is just part of the standard Republican campaign toolkit. They were going to argue that no matter what he did as governor. But to the extent that there's some truth to it (and to the extent that voters believe it), it's because Colorado's political landscape has changed. Hickenlooper is making choices he's never had to make before. And people are noticing.