Veterans for Trump? Stereotype doesn’t match diversity in the ranks.

Bryce Dubee traces his drift toward the Democratic Party to his first Army tour in Iraq in 2004. A year earlier, only weeks after U.S. forces invaded, then-President George W. Bush gave his “mission accomplished” speech. Mr. Dubee realized soon after arriving that the upbeat rhetoric of military and political leaders back home downplayed the reality on the ground.

“It was already grim when we got there,” says Mr. Dubee, who had supported Mr. Bush as the Republican nominee for president in 2000. “And as things went along, I remember thinking, ‘Maybe this is bad.’”

A public affairs officer, he deployed twice to Iraq and once to Afghanistan during a 12-year Army career that ended in 2016, and by then, he had switched political parties. As early voting began two weeks ago in Texas, where he lives in an Austin suburb, the former staff sergeant cast his ballot for Joe Biden. Mr. Dubee favors the Democratic candidate over