Mark Lamb holds a commanding lead in the Arizona 5th Congressional District Republican primary due to his early Trump endorsement, prior statewide name recognition from a 2024 U.S. Senate bid, and consistent polling strength among likely primary voters. As the former Pinal County sheriff, Lamb benefits from law enforcement endorsements and broad appeal across conservative factions in the open seat race to succeed Rep. Andy Biggs. The July 21 primary remains several weeks away, leaving room for late developments such as a major candidate withdrawal, unexpected fundraising surge by challengers like Travis Grantham or Jay Feely, or unforeseen controversies to alter the current trader consensus reflected in the market pricing.