Though the process varies from state to state, redistricting is usually a partisan endeavor. In most cases, a state’s district lines--for both state legislative and congressional districts--are redrawn by the state legislature, and the majority party controls the process. Some states require bi-partisan or non-partisan commissions to oversee the line-drawing. However, the state governor and majority party leaders often control who is appointed to these commissions. At the local level, city council presidents and/or council members usually oversee the redistricting process.
Some states are moving toward involving citizens in the redistricting process and creating truly independent redistricting commissions. In 2008, California voters passed Proposition 11, a referendum establishing an independent redistricting commission made up of citizens. This commission will draw state legislative districts--though not congressional districts--for the 2012 elections. In Illinois, a state representative has proposed legislation to open the redistricting process up to public submissions.
The process, beginning with the mailing of Census forms in March 2010, can take 18 months to two years. The Census Bureau is required to provide states with redistricting data--including population counts by age and race at the block-level--by April 1, 2011, one year from the official Census Day. Many states begin preparations for redistricting, such as assembling redistricting commissions, well ahead of this date. The deadlines for completing state legislative and congressional redistricting plans vary from state to state, although states’ legislatures and commissions must have final redistricting plans in place before the primary elections in spring 2012, as the 2012 election cycle is the first time politicians will be running for office in the newly redrawn districts. At the local level, the timelines for redistricting are highly variable.