While there are other countries, primarily English-speaking ones, which use first-past-the-post (plurality voting) in single-seat constituencies to elect representatives to the national parliament and other legislative bodies, redistricting in the U.S. differs from that in other countries in several key ways.
(a) It is highly decentralised.
(b) It is highly politicised, and partisan gerrymandering is common.
(c) Highly contorted district shapes are common.
(d) courts are involved at many stages of the redistricting process and it is a rare plan that is not challenged either as a racial gerrymander, or a partisan gerrymander, or under other state law grounds (e.g., a failure to preserve political subunit boundaries or a failure of contiguity or of equal population).
Moreover, racial challenges can occur under two quite different and potentially contradictory standards: a Section 2 Voting Rights Act challenge that minority groups had their voting rights diluted versus a claim that race was a preponderant factor in the districting. The worst gerrymandering occurs when one party has trifecta control of state government, i.e., both branches of the legislature and the governorship.
Presently this gives Republicans the advantage, while in much of the previous century, it gave Democrats the advantage. As political polarisation has increased, the level of gerrymandering has also risen. But because the US Supreme Court in 2018 declared that political science approaches to measuring gerrymandering were simply, in Chief Justice Roberts’ words, “sociological gobbledygook”, the burden has shifted to state courts to deal with claims of egregious partisan gerrymandering under state law. But only some state courts have stepped up to this challenge, and in some states, state court justices have shown themselves to be politicians in robes.
Bernie Grofman is a Distinguished Research Professor of Political Science at the University of California, Irvine. Professor Grofman’s research focuses on voting behaviour, redistricting, and the impact of electoral rules on political outcomes. He has published numerous books including A Unified Theory of Party Competition, A Unified Theory of Voting, and Electoral Laws and their Political Consequences along with hundreds of journal articles.