Dave Wasserman, the ubiquitous elections analyst for the Cook Political Report, has been following redistricting for decades—not only was it the subject of his college thesis, but his X handle is literally @Redistrict. As the lead author of Cook’s signature product, the Partisan Voting Index (PVI), Wasserman is in charge of documenting the “lean” of each of the country’s 435 congressional districts—from R+33 in AL-04 to D+40 in PA-03, and all the districts in between. With both parties rushing to redraw district maps in Texas and California, and setting their sights on future states, he’s become one of the most important data oracles in Washington.