Jay Feely leads the AZ-01 Republican primary field with 78% implied probability, driven primarily by President Trump's endorsement after Feely relocated his candidacy from the 5th district at the president's urging. This backing, combined with support from Turning Point USA, has consolidated donor and voter momentum in a primary where national Republican signals carry substantial weight. Former state representative Joseph Chaplik holds 19% amid lingering name recognition from an earlier April poll advantage and Freedom Caucus ties, though recent negative exchanges with Feely over personal and policy attacks have not narrowed the gap. Lower-polling candidates including John Trobough, former party chair Gina Swoboda, and Kari Lake face steep structural barriers after Swoboda's withdrawal for another race and the absence of comparable institutional support. The July 21 primary timeline leaves limited room for late shifts absent major new endorsements or polling surges.