Redistricting does little to change which party people vote for, which can make partisan gerrymanders more effective.

Every decade US state legislators redistrict the congressional districts in their state based on new census information. Over the decades redistricting has become another means by which a political party can gain electoral advantage. In new research using Pennsylvania’s redistricting as a case study, William D. Hicks and Seth C. McKee find that voters in redrawn districts did not change their voting preferences, and that changes in their incumbent candidate or an electoral tide towards the Democratic Party had little or no effect on these choices.