In an email, Austin argued that when the local economy improves, the tendency of voters to blame people they perceive as outsiders — racial minorities and immigrants — diminishes, to the advantage of Democrats and to the disadvantage of Republicans:

Undergirding Trump’s nativist appeal is the fact that it is impossible to separate the interplay of economic prospects and race as a defining issue for the Midwest’s older manufacturing communities. Midwest industrial communities are the most segregated in the nation.

It should come as no surprise, Austin wrote, that

citizens of once tidy, thriving communities are nostalgic for better days. And it should also be no surprise that a latent bias to blame and resent people of color for “what’s wrong” when the economic wheels really come off is today on full display. Particularly when the racism and resentment are stoked by a demagogic President suggesting that immigrants are the problem, or just don’t belong in America.

In those areas where the economy is improving, however, Austin argues,

This dynamic can and is being changed in many communities. Voters in communities that are doing better economically appear less anxious and nostalgic, and more tolerant and forward looking — more interested in issues and less inclined to reward nativism and economic nationalism.

There are aspects of the politics of the Midwest that are unique to the region and there are aspects that are common to the nation at large. One shared trend is the phenomenon cited by Austin: the pattern of 2018 Democratic congressional victories in better-off districts.

The Economic Innovation Group, a Washington think tank that studies regional inequality, ranked all 435 congressional districts into five groups based on their economic condition: the prosperous, the comfortable, the mid-tier, the at-risk and the distressed.

An examination by the group of all of the congressional districts across the nation that flipped in 2018 from red to blue produced intriguing results.

Of the 43 congressional districts that shifted from Republican to Democratic control, 23, more than half, were ranked as prosperous, and seven, or 16.3 percent, were ranked as comfortable. Altogether, almost 70 percent of the districts that switched from Republican to Democratic were ranked in the top two economic categories.

While Austin’s work and the Economic Innovation Group data suggest that one path to Democratic victory lies in expanding the gains the party has made in affluent sections of the country, Muro and Jacob Whiton, a Brookings research analyst, voiced some warnings.

Using measures of income and growth separate from those used by the Economic Innovation Group, Muro and Whiton compared how well each of the 43 flipped districts has done in recent years to how well the states in which these districts are located have been doing.

Muro wrote by email:

Overall we find some suggestion that better economic performance supported red-to-blue flipping leading up to the 2018 midterms, but it’s not at all automatic, or deterministic. Local details, and certainly narratives and memes and political predispositions, are clearly playing a likely larger role.

Polls show that favorable economic trends nationally are not working to the clear advantage of Trump the way they would be expected to by many analysts.