This year, Democrats are playing defense in Senate races, with all the most likely seats to flip currently held by Democrats. As the election nears, several races are tightening, putting Republicans within reach of gaining more Senate seats than anticipated. The states that have shifted most in the Republican challengers' direction are Wisconsin and Pennsylvania. Both feature similar races, with former businessmen challenging longtime incumbent Democratic senators in swing states. A few months ago, both Republican challengers were trailing by more than 5 points, but now the races are much...
