EXCLUSIVE — An Arizona mayor in a major border town who once campaigned alongside Republican Senate hopeful Kari Lake is now endorsing her opponent, Rep. Ruben Gallego (D-AZ), in a state where immigration and border security remain a major vulnerability for Democrats and President Joe Biden.

Nogales Mayor Jorge Maldonado announced his endorsement Tuesday, making him the third border mayor to back Gallego’s Senate bid, in a town that includes a critical point of entry with one side in the United States and its sister city, Nogales, Sonora, in Mexico.