Chris Elmendorf and Doug Spencer have written an important new paper that voting rights folks need to read:

Until the Supreme Court put an end to it in Shelby County v. Holder, Section 5 of the Voting Rights Act was widely regarded as an effective, lowcost tool for blocking potentially discriminatory changes in election law and administration. The provision the Supreme Court left standing, Section 2, is generally seen as expensive, cumbersome and almost wholly ineffective at blocking changes before they take effect. This paper argues that the courts, in partnership with the Department of Justice, could reform Section 2 so that it fills much of the gap left by the Supreme Court’s evisceration of Section 5. The key is to establish rebuttable presumptions that cover the recurring, difficult-to-resolve factual questions in Section 2 cases, and to craft the presumptions so that their application in any given case can be determined using national survey data and off-the-shelf statistical models, rather than vote tallies from local elections and other case-specific data. We propose a set of evidentiary presumptions that meet these criteria; we address the courts’ and DOJ’s legal and practical authority to establish the presumptions; and we show how our presumptions can be implemented using multilevel regression and poststratification (MRP) and extant datasets. In addition to reducing the cost and increasing the predictability of Section 2 litigation, our approach would greatly reduce the dependence of vote-dilution claims on often-unreliable techniques of ecological inference, and would make coalitional claims brought jointly by two or more minority groups much easier to litigate.