From Michael Cooper at the New York Times
Republicans are within reach of gaining control of eight or more chambers in statehouses around the country this fall, according to interviews with Republicans, Democrats and independent political analysts. That would give Republicans the power to draw more Congressional districts in their favor, since the expected gains come just as many legislatures will play a major role in the once-a-decade process of redrawing the boundaries of those districts.
Republicans said they expected to win control of House chambers in Indiana, Ohio and Pennsylvania, and the State Senate in Wisconsin, and saw at least a dozen other states where they have a reasonable chance of winning control of legislative chambers. Democrats acknowledge that they will be fighting to preserve their slim majorities in at least 10 chambers — including State Senates in Nevada, New Hampshire and New York — but say that they see opportunities to gain control of chambers in four other states.
Redistricting, it has often been said, turns the traditional definition of democracy on its head: rather than allowing voters to choose their leaders, it allows leaders to choose their voters.