On Monday afternoon, Sen. Thad Cochran, the first Republican in over a century to win a statewide race in Mississippi and the longest-serving member currently in Congress, announced he would resign from office on April 1. The news wasn’t unexpected — Cochran’s worsening health began stirring up rumors of resignation as early as last year — but it still throws a wrench into the 2018 midterm elections, and in particular, the U.S. Senate map. CONT.
Nathaniel Rakich, FiveThirtyEight