Most legal challenges to redistricting maps based on population deviation center around deviations that are too large. However, there are a handful of cases in which a court has found a map with minimal deviations (under 10%) to be unconstitutional.
What is minimal? The equal population or “one-person, one-vote standard requires general population equality between districts, but there is no precise number or percentage that defines constitutionality. Instead, the Supreme Court interprets this constitutional requirement for congressional districts to mean “strict equality,” and for legislative and other local maps, districts need only to be “substantially equal.” In practice, a clear standard has emerged for legislative and local maps in which courts consider total deviations above 10% to be constitutionally suspect. Conversely, maps with deviations below the 10% threshold are generally acceptable (in equal population terms).
It is important to note that this is a legal “standard, or guideline” but not a rule. The Court has declined to identify any specific percentage that would represent a violation of one-person, one vote. Their reasoning is that as soon as they did, line-drawers would have every incentive gerrymander maps as they pleased, with no restrictions as long as they stay below the stated limit.
The Court has instead used the 10% deviation measure to adjust the evidentiary burdens on the parties to the lawsuit. Thus, if a contested redistricting map has a deviation above 10%, the burden is on the mapdrawer (the defendant being sued, which is usually the state) to prove why the deviations are so high. If the map’s deviation is below 10%, the burden is on the plaintiff to provide additional evidence over and above deviation, showing that the deviations are a result of impermissible line-drawing.
Generally, a districting plan “with a maximum population deviation under 10% will not, by itself, support an equal protection claim.” . . . Rather, plaintiffs in such cases “must show that it is more probable than not that a deviation of less than 10% reflects the predominance of illegitimate reapportionment factors rather than” legitimate considerations such as compactness or the integrity of political subdivisions. Harris v. Ariz. Indep. Redistricting Comm’n, 136 S. Ct. 1301, at 1307.
Challenges against maps with single digit deviations are not common, but they are litigated and in some cases these maps have been overturned. The obvious question of course, is what kind of proof is needed to convince a court that a state legislative or local political map with a relatively low deviation is nonetheless in violation of the 14th Amendment’s equal population mandate? The answer, in a good number of cases, is partisan motivated deviations.
Regional Protectionism
Georgia’s 2001 legislative reapportionment plans for the state senate and house were challenged on equal population grounds and the Supreme Court affirmed the federal district court’s decision to invalidate the maps. It did so on two grounds, the first being “a deliberate and systematic policy of favoring rural and inner-city interests at the expense of suburban areas north, east, and west of Atlanta.” Larios v. Cox, 300 F. Supp. 2d 1320, 1327 (ND Ga. 2004).
Selective Incumbent Protection
The second reason for invalidating plans was “an intentional effort to allow incumbent Democrats to maintain or increase their delegation, primarily by systematically underpopulating the districts held by incumbent Democrats, by overpopulating those of Republicans, and by deliberately pairing numerous Republican incumbents against one another.”
Both techniques benefitted Democrats in control of the redistricting and the court found no other explanation for the pattern of packing Republicans into districts and not Democrats. It was clear to the court that Democrat line-drawers aggressively sought every partisan advantage they could while staying within the 10% guideline; treating the 10% deviation metric as a safe harbor. Indeed at the time, many states viewed the 10% standard as a legal safe harbor within which they could effectuate partisan advantage.
Partisan Deviation Games
Also, in the consolidated cases of Wright v. North Carolina 975 F. Supp. 2d 539 E.D.N.C. 2014 and Raleigh-Wake Citizens Assoc. v. Wake County Board of Elections, 827 F.3d 333 (4th Cir. 2016), evidence showed that the challenged plans under-populated Republican-leaning districts and over-populated Democratic-leaning districts in order to gerrymander Republican victories. This was not the extent of the partisan gamesmanship. The cases involved an unsolicited mid-decade redrawing of the county’s school board and commissioner districts by Republicans in the legislature.
The key takeaway here is that the court did not feel that partisanship alone is a legitimate reason to weight some votes more than others. In both of these cases, the overpopulating, under populating and the incumbency protection, are all acceptable considerations when redistricting, but only if they are applied evenly or at least without malice towards the opposing party. According to the Court, if they are created in a pattern that consistently benefits the voters of one party over another by affecting the relative weight of their vote, it is impermissible under the 14th Amendment.
The Georgia case majority opinion called these practices “partisan deviation games.”
Going Forward
Since these two cases have been decided, the Supreme Court has disavowed hearing partisan gerrymandering cases in federal courts Rucho v. Common Cause, 588 U.S. ___ (2019)
That does not mean that redistricting maps with deviations below 10% are free from scrutiny because equal population challenges are a separate legal claim.
The Rucho holding could also influence how courts view partisanship in the equal population context. Some academics view cases like these as partisan gerrymandering cases masked as equal population challenges, and anticipate similar challenges after Rucho shut the door on straightforward federal partisan gerrymandering claims. Others believe these cases have limited holdings and minimal precedential value. (Joshua A. Douglas & Michael E. Solimine, “Precedent, Three-Judge District Courts, and the Law of Democracy” 107 THE GEORGETOWN LAW JOURNAL, 413, 427 (2018))
The 2020 redistricting cycle will likely shed light on this question.
