The use of Congressional redistricting for partisan advantage goes back at least as far as 1812, when the Massachusetts Legislature invented what has become known as the “gerrymander.” Last month’s election proved again that the gerrymander still roams the land.

The Constitution requires congressional districts be redrawn after each census so that the House of Representatives will truly be representative. All else being equal, if party affiliation played no part in how the lines were drawn, we should expect that, in the first election following redistricting, the percentage of votes cast for the two parties in House elections nationwide would be close to the percentage of representatives from each party elected.

But November’s vote, the first election after states redistricted in response to the 2010 Census, showed the power of the mapmakers. An Associated Press vote tally found that Democratic House candidates across the nation received more than 1 million more votes than Republicans, but Republicans came out with a 243-201 seat House majority.