The road to political success for the national parties continues to run through middle suburbs:

On one side of that divide is growing Democratic strength in white-collar suburbs recoiling from Trump; on the other is continued Republican dominance in rural places and blue-collar communities that flocked to Trump in 2016 and haven’t wavered much since. These divergent forces explain why Democratic opportunities are expanding in well-educated suburban districts around major metropolitan areas all over the country while the party is still facing an uphill climb in almost all the House seats outside metropolitan areas that it hoped to contest this year.

The Washington race between first-time Democratic candidate Kim Schrier, a pediatrician, and Republican Dino Rossi, a three-time GOP nominee for statewide office, is one of several contests that capture both of those dynamics inside the same district. Democrats this year are mounting serious challenges for Republican-held seats that sprawl from suburban into rural areas around Richmond, Virginia; Lexington, Kentucky; Charlotte and Raleigh, North Carolina; Cedar Rapids and Des Moines, Iowa; Topeka, Kansas; Columbus, Ohio; Springfield, Illinois; and parts of upstate New York, among other places.

Republicans have controlled each of these districts for years, typically posting comfortable margins in both their rural and suburban areas. But the results in them this fall will pressure-test the electoral trade that Trump is imposing on his party: growing strength in small-town and rural communities offset by growing skepticism and resistance in many white-collar suburbs, particularly among women. The intensely divisive confirmation battle over Supreme Court Justice Brett Kavanaugh appears poised to magnify the trends on both sides of that line.

The main contours of the political battle continues to hold: Democrats get votes from big cities and close suburbs, Republicans get votes from rural areas and exurbs, and the two parties fight over the middle suburbs characterized by relatively educated and wealthy residents with some pockets of poorer residents as well as various levels of racial and ethnic diversity. This was the pattern in 2016 (see earlier posts about Clinton winning in the Chicago suburbs, Trump losing ground in suburbs, and changes in suburban voting patterns) and it appears to be true in the 2018 elections (see recent posts here and here).