Mark Lamb wins Arizona House GOP primary amid misconduct allegations

Mark Lamb won Arizona’s 5th Congressional District Republican primary, overcoming a late surge of attacks over allegations of sexual impropriety and misconduct that had threatened to derail a race once seen as a lock for the former Pinal County sheriff.

The result leaves Republicans sending into the general election a candidate built around law-and-order credentials and a direct endorsement from President Donald Trump. Lamb, who led the Pinal County Sheriff’s Office before entering the race for the open House seat, defeated construction business owner Daniel Keenan after the contest sharpened into a test of whether the allegations would outweigh Lamb’s public profile as a hard-line former sheriff.

The race opened up because Rep. Andy Biggs was running for governor. That made Arizona’s 5th District one of the most closely watched Republican contests in the state, especially after the misconduct claims became central to the primary and Keenan made them the focus of his closing argument. Keenan spent heavily on attack ads aimed at Lamb as early ballots approached, while Lamb responded by sending Keenan a cease-and-desist letter.

A Remington Research Group poll of 650 likely Republican primary voters in the district, conducted July 5 through July 7, showed how unsettled the race had become. The survey carried a margin of error of plus or minus 3.8 percentage points at the 95% confidence level, underscoring that what had started as a comfortable path for Lamb had turned competitive in the final stretch.

Keenan tried to cast himself as the more reliable Trump-aligned option, describing himself as the “most effective pro-Trump” choice even as Lamb held the president’s endorsement. But in the end, Republican voters stuck with Lamb, a sign that his identity as a sheriff and his support from Trump carried more weight than the allegations dogging his campaign.

Lamb’s victory also means Arizona Republicans are sending a nominee to November who has already been hardened by a bruising primary fight. With Biggs leaving the seat open and the party backing a candidate who turned a misconduct scandal into a test of loyalty and toughness, the general election campaign will begin with Lamb already known statewide and already battle-tested.