Gerrymandering: How Politicians Rig Elections

This video from Vox looks at gerrymandering in the United States.

It begins with a description that "the way elections are supposed to work is voters choose their politicians but in America politicians often get to choose their voters."

The United States has 435 electoral districts, and those districts need to be drawn and re-drawn based on changing populations. Unfortunately, in most states politicians draw the district lines and "the results are totally predictable": state legislators can create districts that favor their party. 

North Carolina is used as an example of this situation - Democrats received over 50% of the house votes in 2012, but won only four house seats to the Republican's nine. This is due to district lines that "cluster the state's Democrats together into only a few districts with huge majorities" whereas the state's Republicans are spread out in more districts with slimmer majorities.

The video ends by describing that there is an alternative to partisan gerrymandering and gives Canada's electoral system as an example where they use independent commissions to draw district lines.