Challenges of Redistricting

When discussing redistricting, I’ve heard individuals raise the question, “Why don’t we just let computers draw the lines and be done with it?” And why not? We let computers run so many aspects of our lives, why not this one as well? While computers and GIS software are fundamental to the completion of redistricting tasks, programming the computer to draw the maps requires firmly established criteria. Even with clear criteria, there are thousands of legal maps that can be produced, and adjudicating between these maps may be more art than science.

Redistricting is a fundamentally political process and, like many political topics, it is not without controversies. Many of these conflicts stem from the absence of significant federal guidelines for redistricting. Consequently, the processes by which individual states draw their district lines vary significantly.

At present, one of the largest controversies is over who should draw the district lines. In a majority of states, including North Carolina, the state legislature is responsible for drawing both the congressional and state legislative district lines. Should legislators be able to “choose their voters” or should it be an independent commission? How can we determine a commission’s independence, especially regarding who appoints them?

Other debates swirl around how the lines should be drawn. There are two federal criteria—equality of population and protection of the minority vote. These are the only guidelines in North Carolina and 18 other states, but even these criteria are less than settled. Additional criteria that some states consider during redistricting, and some of the questions that must be addressed, include:

• Contiguity. Although this is generally practiced, a non-contiguous district is not necessarily a bad redistricting plan. Redistricting might prioritize municipal boundaries, and, due to annexation, not all municipal boundaries are contiguous (e.g., Holly Springs in Wake County).
• Compactness. How to define and measure compactness? Is a compact district necessarily good, a non-compact district bad? (No.)
• Align with existing political boundaries by following county or municipal lines where possible.
• Maintaining communities of interest. How do we define a community of interest? Whose interests are captured?

These priorities can conflict with each other. Valuing communities of interest will often end up reducing compactness of the districts. Valuing compactness and equal population above all else will make it difficult for individuals in smaller or diffuse communities to gain effective representation. Additionally, where we start drawing the districts will influence what the final product looks like.

Redistricting is about balancing these competing interests. And while data can inform the debate, no amount of data or data science will help us in identifying and adjudicating between these interests. Defining clear objectives for redistricting—and their order of preference—is a political discussion.

Ultimately, there will be controversies around redistricting because we participate in a winner-take-all political system. And in any election, who wins and who loses is often strongly influenced by how the lines are drawn.