Redistricting is the act of using census data to assign geographical boundaries for electoral districts. Originating from a simple constitutional mandate designed to ensure equal access to the government, the modern process is often criticized as a tool for political machines. Redistricting is intended to assign political representation in the US House of Representatives proportionally across regions, regardless of population density. However, geographic boundaries are historically drawn in conspicuous ways that reflect concentrations of an incumbent's supporters in a process called gerrymandering. In response to the widespread perception of such abuse, several states have created non-partisan agencies to redistrict the electorate in order to ensure that the spirit of the law, not the political persuasion of the moment, controls representation allocations.