The Midwest will decide who wins the White House in November. Much has been written about Kamala Harris’s not-so-subtle appeal to Michigan’s Muslim voters, and her choice of Tim Walz as running mate rounds the ticket out with a Minnesota governor who once praised an extremist Muslim cleric as a “master teacher”. But away from the cheap tactics of identity politics — which will only fly with so many Midwesterners — Harris and Walz may have more trouble convincing the...