The Philadelphia redistricting following the 2000 Census was a drawn out and bitter affair, but to the outside observer, it was somewhat difficult to understand why.
The battle over redistricting following the 1991 Census turned on a small but significant new demographic in a city that had otherwise been losing population for years - the 100,000 Latino residents who were newly counted in the Census.
This redistricting effort focused on several stark demographic facts from the 2000 Census - the state's major cities were losing population to the suburbs, forcing major changes in state legislative districts, and Pennsylvania was growing far more slowly than other states, costing it two seats in Congress. The solution, imposed by Republican leaders, wound up in the U.S. Supreme Court.
The post-1991 census redistricting showed that state legislative leaders had little trouble protecting their own, but were unable to come to agreement on which incumbents to sacrifice when the state's Congressional delegation dropped from 23 to 21 after the 1991 Census showed Pennsylvania growing far more slowly than other states.