… If you’re a Democrat thinking about running for office in a swing district in 2018, you’re hoping Trump’s ratings stay on the mildly to very unpopular side of the scale. Actually, “mildly unpopular” might not be good enough. The relationship between presidential approval ratings and congressional elections is rough, and Republicans have some pretty clear structural advantages. The GOP could hold the House even if Trump remains about as unpopular as he is now. CONT.
Harry Enten, FiveThirtyEight