While such one-party dominance is an almost surefire cure for gridlock, analysts say, it also points to the increasing balkanization of state governments as Democrats and Republicans move away from the political center. The concentrated power has sparked backlashes in Colorado and Minnesota on the left and Wisconsin and Michigan on the right.

“I think it’s part of a trend of party polarization that we’ve seen for the last decade or so,” said Seth Masket, a political science professor at the University of Denver. “The voters are increasingly being offered candidates who are either very liberal or conservative in elections, and there are far fewer of the moderates that we used to see win.”…

He noted that the danger for any one-party state is overreach, and some legislators already are feeling the heat for pushing through too many bills relying on one party’s dominance of the levers of state power. In Colorado, recall campaigns organized by gun rights advocates have turned in signatures aimed at ousting two Democrats, Senate President John Morse and state Sen. Angela Giron, for their votes in favor of gun control bills…

“Colorado Democrats are showing the same hubris as Republicans did 10 years ago,” said Denver-based Republican Party strategist Dick Wadhams. “The Democrat legislature is not popular, so I think the potential for a Republican comeback is there.”