Former Pinal County Sheriff Mark Lamb leads the July 21 Republican primary for Arizona’s 5th Congressional District, an open seat vacated by Rep. Andy Biggs, due to his strong name recognition, early polling leads exceeding 50 percent among likely GOP voters, and endorsements from conservative groups. Late entry in October 2025 allowed Lamb to consolidate support quickly in the East Valley district. Jay Feely and Travis Grantham, early filers with lower profiles, have withdrawn, leaving Daniel Keenan as the remaining opponent. Recent developments include May 2026 reports of allegations against Lamb and his decision not to participate in candidate debates, which traders appear to weigh against his fundraising and organizational advantages as the primary approaches.