With control of both the House and the Senate in play on Election Day 2018, one unlikely state could prove pivotal: Minnesota. Known as a stubbornly Democratic state—Minnesota hasn’t voted Republican in a presidential election since 1972—it is sometimes written off by Republicans. The state has produced a roster of famously progressive politicians, from Hubert Humphrey and Walter Mondale to Paul Wellstone and Keith Ellison. Also Al Franken. When he resigned his Senate seat last year after being caught up in the #MeToo movement, Democratic Gov. Mark Dayton appointed his own lieutenant governor, Tina Smith, to fill the seat. Smith...