Emily Bazelon for NYT Magazine:
The Republicans tried hard to keep the mapmaking process a secret. But they weren’t successful. In the first of two lawsuits brought by Democratic voters, three federal judges berated Republican leaders in 2012 for ‘‘flailing wildly in a desperate attempt to hide’’ their methods. A year later, the court ordered Republicans to turn over three computers. One appeared to have been tampered with, and a hard drive on a second computer had been wiped clean. But in 2016, a computer expert hired by the plaintiffs in the second lawsuit found, on another hard drive, spreadsheets that used a powerful new gerrymandering tool, based on sophisticated computer modeling.
The tool was created by Keith Gaddie, a political-science professor at the University of Oklahoma. Gaddie devised a way to measure partisanship for every precinct, which two Republican aides and a consultant used to draw a series of possible maps. They matched those maps against a regression analysis that Gaddie devised, which showed how the districts would perform, in the aggregate, in the event of any likely electoral outcome. By modeling everything from a typical split between Republicans and Democrats to a big swing toward either party, Gaddie’s techniques allowed the mapmakers to distribute voters with maximum advantage for Republicans, without fear of spreading their own supporters too thinly and thus imperiling safe seats….
Among the experts who think the means now exist for courts to referee gerrymandering fairly is Keith Gaddie, whose work enabled Wisconsin’s Republican mapmakers. In a brief submitted to the Supreme Court in August, Gaddie and Grofman argue that social scientists can identify exactly how much the differential treatment of voters is ‘‘man-made’’ — a result of deliberate efforts by the party in power to penalize the opposition. I called Gaddie to ask how his stance squares with his earlier role. ‘‘I didn’t draw any maps in Wisconsin,’’ he said. ‘‘I helped them construct measures and tools. They made decisions and drew lines.’’ When I asked if he would do the same thing again, Gaddie said, ‘‘I don’t do this work anymore,’’ and hung up.