Page:Allen v. Milligan.pdf/34

Rh But even if the maps created by Dr. Duchin and Dr. Imai were adequate comparators, we could not adopt the map-comparison test that Alabama proposes. The test is flawed in its fundamentals. Districting involves myriad considerations—compactness, contiguity, political subdivisions, natural geographic boundaries, county lines, pairing of incumbents, communities of interest, and population equality. See Miller, 515 U. S., at 916. Yet “[q]uantifying, measuring, prioritizing, and reconciling these criteria” requires map drawers to “make difficult, contestable choices.” Brief for Computational Redistricting Experts as Amici Curiae 8 (Redistricting Brief). And “[i]t is easy to imagine how different criteria could move the median map toward different … distributions,” meaning that “the same map could be [lawful] or not depending solely on what the mapmakers said they set out to do.” Rucho v. Common Cause, 588 U. S. ___, ___–___ (2019) (slip op., at 27–28). For example, “the scientific literature contains dozens of competing metrics” on the issue of compactness. Redistricting Brief 8. Which one of these metrics should be used? What happens when