Optimal Gerrymandering: Sometimes Pack, But Never Crack," working paper

One of the more curious features of American democracy is that electoral boundaries are drawn by political parties. In order to ensure a notion of equal representation, the Constitution of the United States provides that “Representatives and direct Taxes shall be apportioned among the several States which may be included within this Union, according to their respective Numbers.” Since populations change over time, the Constitution also provides a time frame according to which representation shall be adjusted—“ … within every subsequent Term of ten Years, in such Manner as they shall by Law direct”—where “they ” represents the states. In practice, this leaves the process of redistricting to state legislatures and governors. History has shown that political parties act in their own interests; redistricting is no exception, and the advantages gained can be large. From Massachusetts’s Elbridge Gerry in 82 (after whom the term “Gerrymander ” was coined) to the recent actions of Texas Representative Tom DeLay, American politicians have used the redistricting process to achieve partisan political ends. Most recently, the much publicized Republican redistricting in Texas in 2003 caused four Democratic congressmen to lose their seats and would have been even more extreme but for the Voting Rights Act, which effectively protected nine Democratic incumbents. Other particu-larly stark current examples include Florida, Michigan, and Pennsylvania—states that are evenly divided, but whose delegations to the 09th Congress collectively comprised 39 Republicans and 20 Democrats. Democrats are also familiar with the practice; although President George W. Bush won Arkansas by more than 0 points in 2004, the state’s delegation to the 09th Congress