Is Mark Brnovich conservative enough for Arizona?

Mark Brnovich, the attorney general of Arizona and a leading Republican candidate for Senate, boasts the sort of establishment credentials and prominent statewide profile that have given him a running start as he competes in one of the most high-profile races of the midterm elections.

His studded résumé, in contrast with an array of lesser-known GOP rivals, suggests some continuity with an individualist style of Republican politics that, while often idealized, has long been venerated in the historically conservative Copper State. As a college freshman, for instance, Brnovich interned with the self-proclaimed...