About a year ago, I read the book Ratf**ked: Why Your Vote Doesn't Count, by David Daley. It is an eye-opening account of how some Republican strategists figured out that by flipping a few state legislatures from blue to red, the Republicans would get to control the redistricting process after the 2010 Census and draw the maps for those states to favor their party. The book has chapters on Pennsylvania, North Carolina, Michigan, Ohio, Florida, Wisconsin, and Arizona -- the states where we have seen increased attention since. The strategy was quite successful. The books is worth your time, as a means of better understanding what happened in 2010 and sorting through the challenging issues associated with the Constitutionality of gerrymandering.
In today's Washington Post, James Hohmann describes (without reference to Daley's book, strangely) what some left-leaning groups are doing between now and the midterm elections to try to run that strategy on behalf of Democratic candidates. Midterm elections tend to favor the party that does not hold the Presidency, and the Tea Party was ascendant while the Democrats were snoozing in 2010. But in 2018, the midterm effect favors the Democrats, and in 2020, they will be driving high turnout due to their dissatisfaction with President Trump. So they are poised to make gains. What they won't have is an opposing party that is not paying attention. There is nothing magical in the way Democrats would figure out which races to target, so I expect the Republicans to contest them vigorously. If you are in one of those districts, I don't envy the political ads and robocalls you will be experiencing over the next two months.