Donald Trump so dominates the media landscape that he crowds out other news. So what may be the most important political development of our time—the death of partisan gerrymandering—may not be receiving the attention it deserves. Following the 2010 census, and the Republican landslides in the midterm elections of that year, G.O.P. leaders at the state level created remarkably cynical legislative maps for both state offices and the U.S. House of Representatives. They drew district lines that gave Republicans many more seats than were justified by their over-all statewide numbers. In Pennsylvania, for instance, Republicans received only about half the statewide votes, but they now control thirteen of the eighteen seats in the House. Yet the Republicans may have overreached. A series of court decisions in recent weeks—in North Carolina, Pennsylvania, and at the United States Supreme Court—have demonstrated that the judicial branch of government is mobilizing to end this shameful and destructive legislative practice.
The legal assault began on January 9th, when, in a powerful two-hundred-and-five-page opinion by Judge James A. Wynn, Jr., a three-judge panel struck down the North Carolina congressional-district lines. What’s most important about Wynn’s opinion is that he seems to have solved the biggest problem with judicial review of gerrymandering: the standard of review. Drawing district lines will always involve some degree of political calculation, but judges have struggled with the question of how much politics is too much. What rule should judges follow to determine if a gerrymander violates the Constitution? Wynn’s test is straightforward. As Nicholas Stephanopoulos, a professor at the University of Chicago Law School, puts it, under this standard, “a district map is invalid if (1) it was enacted with the discriminatory intent of benefiting a particular party and handicapping its opponent; (2) it has produced a discriminatory effect in the form of a large and durable partisan asymmetry in favor of the mapmaking party; and (3) no legitimate justification exists for this effect.” In plain English, Wynn’s test means that if politicians draw district lines solely to protect their partisan interests, they’re invalid. (The Supreme Court put the decision on hold, but this is a routine step when the Justices are considering a similar issue.)