The Third Criterion: Compactness as a Procedural Safeguard Against Partisan Gerrymandering

Abstract

The health of democracies, of whatever type and range, depends on a wretched technical detail-electoral procedure. All the rest is secondary.' In the aftermath of the decennial census, reapportionment and its wayward stepchild gerrymandering have again become topics of the hour. In 1991 or 1992, based on the new census, state legislatures will establish new boundaries for congressional and state legislative districts. 2 In order to conform to the constitutional mandate that districts have equal populations 3-"one person, one vote" 4-states will have to redraw district lines to account for population shifts that have accumulated over the past ten years. Yet reapportionment, made necessary by fidelity to democratic principles, also will bring with it gerrymandering. Gerrymandering, broadly speaking, is any manipulation of district lines for partisan purposes. 5 There are different varieties of gerrymandering, including racial gerrymandering, 6 remedial racial gerrymandering, 7 and collusive bipartisan gerrymandering. 8 Partisan gerrymandering, the most common kind

Can Compactness Constrain the Gerrymander?

“…Lowenstein and Steinberg (1985) argue that compactness constraints are biased, in the US benefiting Republicans over Democrats (but more generally harming parties whose support base is more clustered). The argument is dismissed for lack of supporting evidence by Polsby and Popper (1991) but is supported by simulations provided by Altman (1998).…”

“…In principle the scope for gerrymandering is large and for this reasons lawmakers and courts have advanced criteria to limit it. Perhaps the three most common criteria are that electoral constituencies should possess equality of population (equinumerosity), contiguity, and compactness (Niemi, Grofman, Carlucci, and Hofeller, 1990;Polsby and Popper, 1991). The arguments for equinumerosity and contiguity are relatively simple; the arguments for compactness is more difficult.…”

“…Without something like compactness anything goes: it is possible to satisfy contiguity and place any set of people together in a single constituency subject only to the size constraint (Polsby and Popper, 1991). Advocates also argue the converse however: that "a requirement of compactness would prevent effective gerrymandering" (Polsby and Popper, 1991) and that compactness acts as a "prophylactic measure that limits the possibility of legislative gerrymandering" (Stern, 1974). Thirty five US states now require that constituencies be compact (Chambers and Miller, 2009).…”

Measuring legislative boundaries

“…The most common such measure compares the length of the district perimeter to the square-root of its area (Schwartzberg, 1966;Cox, 1927;Weaver and Hess, 1963;Polsby and Popper, 1991). The state of Colorado measures entire districting-plans by summing the length of all district boundaries.…”

Redistricting California: An Evaluation of the Citizens Commission Final Plans

“…Niemi et al (1996) showed that aggregate statistics produced by these measures generally lead to similar conclusions about specific redistricting plans, so the precise measure we choose is not likely to affect our conclusions. We use the measure proposed by Polsby and Popper (1991): It ranges from zero to one, with higher values indicating greater compactness.…”