This story originally appeared on Spotlight PA.
This article is part of a yearlong reporting project focused on redistricting and gerrymandering in Pennsylvania. It is made possible by the support of Spotlight PA members and Votebeat, a project focused on election integrity and voting access.
Pennsylvania became less white and more concentrated in and near cities during the past decade, changes that have major implications for state lawmakers as they prepare to draw new political maps.
Because of Pennsylvania’s sluggish population growth compared to other states, it will lose one of its 18 congressional seats. That creates a politically fraught task for the Republican-controlled legislature, which is charged with drawing a new map that must be approved by Democratic Gov. Tom Wolf.
A complicated process also awaits the Legislative Reapportionment Commission, a panel of two Democratic leaders, two top Republicans, and an appointed, tie-breaking chair that has the final say over the state legislative maps.
The commission is awaiting final data so it can create a draft plan for the public, and population numbers released last week by the U.S. Census Bureau show they’ll face many challenges and choices.
“Generally I look at this as a Rubik’s Cube problem,” said David Thornburgh, president and CEO of the good-government group Committee of Seventy and managing director of Draw the Lines.
Mapmakers move a boundary for one district, which then requires them to adjust boundaries to a neighboring district and so on — all while meeting standards set out in the state constitution as well as principles widely touted by anti-gerrymandering advocates.
Here are four takeaways from the new census data and what it means for the state House and Senate maps:
Shrinking versus expanding
One of the basic redistricting principles is equal (or at least, very similar) populations in each district.
With Pennsylvania’s population now topping 13 million, an ideal state House district should have just over 64,000 people, while state Senate districts should have 260,000.
There are dozens of House and Senate districts, primarily in rural areas of western and northern Pennsylvania, where the population is lower than the new benchmarks, according to an analysis by Penn student Gianni Hill. Republican-held districts are more affected than Democratic ones.
Those districts could be combined with others nearby, while mapmakers could also move districts from the west or north to another part of the state experiencing more population growth.
All eyes on the southeast
In 2011, the House map eliminated districts in Allegheny, Erie, and Philadelphia Counties and added seats in Allentown as well as Berks, Chester, and York Counties.
Daniel McGlone, a senior GIS analyst at Philadelphia-based Azavea and project manager of the redistricting tool DistrictBuilder, said the choice benefitted fast-growing Republican suburbs over urban areas. Now, a decade later, the trend has reversed: Democratic areas are growing faster than Republican ones, he said.
Population growth was primarily seen in the southeast and Lehigh Valley, as well as in south-central counties like Cumberland and Lancaster.
The Legislative Reapportionment Commission will have a few options when it begins redrawing the maps with the new data.
It could start with a clean slate, drawing fresh districts to account for population shifts and the growing number of Hispanic, Asian American, and Pacific Islander residents.
“There’s a perception that it’s hard to start from a blank map, but it isn’t,” said Suzanne Almeida, redistricting and representation counsel for Common Cause.
In addition to nearly equal population, the Pennsylvania Constitution requires districts to “be composed of compact and contiguous territory.” It also states that “no county, city, incorporated town, borough, township, or ward shall be divided” unless absolutely necessary.
There are also additional criteria mapmakers can adhere to as recommended by good-government and anti-gerrymandering advocates, like agreeing to only split a locality when necessary to ensure equal representation for non-white Pennsylvanians. The grassroots group Fair Districts PA pushed to mandate stricter rules, but the legislature failed to take up the reforms.
Almeida said the commission will have an incredible amount of public input and data to start with. “They just need to make those difficult decisions,” she said.
Thornburgh, of the Committee of Seventy, said starting from a blank map “might be asking a lot,” as the Democratic and Republican leaders involved have 253 sitting lawmakers to consider.
The more likely approach, he said, would be to look at the House and Senate districts, see which ones are above or below the new population benchmarks, and make adjustments from there — while keeping in mind public input and constitutional requirements.
“This is why most folks say this is more art than science,” Thornburgh said.
Moving one of the least populated House districts from the northwest or southwest to Philadelphia — home to some of the most overpopulated districts — might seem like a no-brainer. But McGlone of Azavea noted that mapmakers must also be conscious of existing so-called majority-minority districts that satisfy the Voting Rights Act and ensure non-white Pennsylvanians are given the opportunity to elect the candidates of their choice.
There are districts in north Philadelphia that have lost population, for example, but mapmakers can’t let them grow into whiter areas too much without tipping the balance.
Republicans may argue that Cumberland County is a better fit for a new House district, he said, as it saw some of the greatest population growth during the last decade.
Spotlight PA is an independent, non-partisan newsroom powered by The Philadelphia Inquirer in partnership with PennLive/The Patriot-News, TribLIVE/Pittsburgh Tribune-Review, and WITF Public Media.