Despite the near-certainty that Democrats will win the national popular vote for House races in November, I still estimate a 10% probability (and other forecasters, up to 25%) that Republicans will retain control. Why? Gerrymandering.

More than anyone else, Tom Hofeller was responsible for the modern age of aggressive redistricting. He carried out this program to an extent that nobody in either party had ever done before. To get an idea of how his work altered and eroded American democracy, see this Atlantic profile of his work. Reid Wilson writes about his life in The Hill.