Three candidates are vying to become the Republican nominee in Arizona's vast 1st Congressional District.
The district takes in the state's high country, low desert and tribal land, including the Navajo Nation, Flagstaff and the suburbs north of Tucson. At 55,000-square miles, it's bigger than half of the U.S. states.
It was drawn to be competitive but has leaned Democrat since 2012.
Retired Air Force pilot Wendy Rogers, Arizona state Sen. Steve Smith, and attorney and farmer Tiffany Shedd all want to be the one to try to flip it to the GOP. Their priorities include securing the border, defending gun rights and limiting the federal government's reach.
Whoever wins the Aug. 28 primary will take on Democratic incumbent Tom O'Halleran in the November general election. He has served one term.