A zone and Trump’s order cover Arizona’s four border counties – Yuma, Pima, Santa Cruz and Cochise – except for a 62-mile stretch of Pima County controlled by the Tohono O’Odham Nation.

The tribe’s ancestral lands span the border, and roughly 2,000 of 34,000 members live on the Mexican side. Tribal leaders declined opportunities to discuss the situation. Even before the ...