Drawing electoral districts to accommodate incumbents, a process known as gerrymandering, is one of the principal but unprincipled means used by Pennsylvania lawmakers to ensure their longevity.

A look at Pennsylvania's electoral map, with its amoeba-like legislative districts, is the most obvious proof of the politicians' dedication to gerrymandering for their own advantage.

A far less obvious aspect of the process crosses the line from political chicanery to injustice and should be eliminated.

The U.S. census counts prison inmates as residents of the political districts in which they are incarcerated, rather than the districts where they lived before being arrested. Even though those inmates may not vote while in prison, they are counted by the state as residents when the politicians draw their own electoral districts in the wake of each census.

Results of that are dramatic. A study last year by the Prison Policy Initiative found that eight state legislative districts in Pennsylvania would not comply with the federal "one person, one vote" civil rights standard if non-voting state and federal prisoners in those districts were not counted as district residents. That means that voters in those districts, mostly in rural south-central Pennsylvania, are over-represented while those in the districts from which the prisoners came are under-represented.

Since 40 percent of the state's prisoners are from Philadelphia but the vast majority of prison beds are in rural areas outside the city, the gerrymandering falsely inflates the voting populations of those rural districts.

New York State had a similar gerrymandering protocol until recently, when the legislature outlawed prison-based gerrymandering. As in Pennsylvania, New York prisons predominantly are in rural areas while most of the inmates come from more populous urban areas.

Pennsylvania should follow New York's lead in ending prison-based gerrymandering.