Walz was a hit in the Midwest. He’s a ‘question mark’ in the Sun Belt.

Tim Walz helped Kamala Harris fire up the base on his Midwestern home turf.

Now, Democrats are about to find out how he plays outside that region. The new running mates are turning their attention from the Rust Belt to the Sun Belt — testing whether Walz’s folksy, Midwestern brand can resonate beyond middle America.

Harris’ campaign is betting that Walz’s biography — he is a former schoolteacher and football coach who grew up in small-town Nebraska, served in the Army National Guard and held a battleground House seat in Minnesota for over a decade before winning two terms as the state’s governor — and his unassuming demeanor will appeal beyond the Midwest.

But Walz is largely unknown outside his home state. He has more limited experience with the southern border, a crucial issue in this election but especially in Arizona, where the campaign will make an appearance on Friday as part of its battlegrounds tour. It’s the home state of one of Harris’ rejected contenders, Sen. Mark Kelly.