Objective. The goal of the study is to empirically assess the extent of partisan and incumbent gerrymandering in the 2000 congressional redistricting. Critics of congressional redistricting have argued that recent partisan gerrymandering severely undermines electoral competitiveness to the point of violating constitutional equal protection standards.

Method. We first analyze the legal precedents and arguments central to the contemporary redistricting debate. We then analyze district-level data measuring the change in a congressional incumbent's presidential party vote share before and after the 2000 redistricting. We conduct regression analyses that test for partisan and incumbent gerrymandering effects with an eye toward noting implications for the Voting Rights Act, particularly majority-minority districting.

Results. We find that recent redistricting significantly contributed to a further decline in electoral competitiveness; however, most of this decline in competitiveness came through incumbency protection, not partisan gerrymandering. Majority-minority districts lost about 5 percent incumbent party vote share, though only 3 percent in southern states.

Conclusion. Given these results, we conclude that the logic of partisan gerrymandering is at variance with the mandate of racial redistricting. One effect of establishing a strict judicial standard limiting statewide partisan biases would be to restrict states' capacity to draw majority-minority districts.