Greg Sargent at WaPo on the structural difficulties Democrats face in taking back the U.S. House: “[E]ven in … big swing states [Ohio, Pennsylvania, Wisconsin, Michigan, and North Carolina] Republicans have large majorities in the state legislatures — a holdover from 2010 redistricting on the state level…. But even if Democrats were to get something approaching neutral maps in these big states, [Cook’s David] Wasserman estimates, it could result in just a couple more seats in each state…. [B]eyond the problem of redistricting is the even more serious problem (for Democrats) of population distribution.”