… As the share of voters who split their tickets has steadily declined since the 1970s, each party’s roster of seats in the House increasingly reflects its voting coalition in presidential elections. …
The sharply polarized nature of Trump’s appeal—which has generated magnetic attraction for blue-collar and non-urban whites, broad opposition among minorities, and unusually high resistance among white-collar whites—has the potential to deepen this sorting process, analysts in both parties agree. …
All initial evidence suggests Trump’s presidency—with its deeply polarizing approaches to immigration, trade, health care, climate, and foreign policy—will widen, rather than narrow, the fissures that emerged around in his election. That means for 2018 and beyond, each party’s electoral target list may grow increasingly focused on the members caught, in effect, behind enemy lines: the last few Democrats representing heavily blue-collar districts and the larger number of Republicans in mostly white-collar suburban seats. CONT.
Ronald Brownstein & Leah Askarinam, The Atlantic