A conservative political group, Club for Growth, is spending $250,000 in the closing stages of Arizona's Republican primary to salvage the congressional campaign of Mark Lamb, a Trump-endorsed sheriff who has built a "family values" image but now stands accused, along with his wife Janel, of being swingers whose lifestyle allegedly wrecked a friend's marriage. The scandal matters because Lamb, 53, is a prominent MAGA figure running for Arizona's 5th Congressional District, and the allegations threaten a candidacy that Donald Trump has publicly and firmly backed.

Lamb, the former Pinal County sheriff, is reportedly accused by multiple women of extramarital affairs and of sending lewd texts and explicit photos; he has dismissed the claims as "lies." Club for Growth has run ads touting his law-enforcement record and released a poll showing his support at 60 per cent ahead of the 21 July primary. His opponent, construction firm owner and political newcomer Daniel Keenan, has seized on the scandal, branding Lamb "a disgrace" and "unfit for office," while Trump has so far not withdrawn his endorsement.