Businessman Zach Lahn, a political newcomer, achieved a significant upset in Iowa's Republican gubernatorial primary, defeating President Donald Trump's endorsed candidate, Representative Randy Feenstra. Lahn's victory marks a rare setback for Trump in a primary season where his picks generally succeeded. This win is also seen as a potential breakthrough for the "Make America Healthy Again" (MAHA) movement, which advocates against widespread pesticide use and for regenerative farming practices, aligning with Lahn's criticisms of large agricultural corporations.

Lahn's campaign successfully fused traditional conservative themes—such as a total abortion ban and removing liberal ideology from schools—with an aggressive critique of corporate agriculture and its impact on public health and the environment. He vocally opposed the consolidation of farmland under corporate ownership, criticized liability protections for pesticide manufacturers, and linked agricultural chemical use to public health concerns. Lahn highlighted Iowa's drinking water quality issues, particularly nitrate contamination, and the state's rising cancer rates.

In his victory speech, Lahn declared, "I will take on the big ag cartels. I will break up their monopolies, and I will get Iowa farmers a fair deal." He also specifically mentioned Iowa as having the "fastest growing cancer rate in the world," attributing it to the unchecked influence of "big ag and big pharma." Lahn further pledged to ban H-1B visa holders from state government and university jobs and proposed requiring state contractors to disclose their planned employment of Iowans.

Lahn's win was largely fueled by his appeal to conservative grassroots supporters and MAHA activists, who felt the Trump administration had not adequately addressed environmental health concerns related to agriculture. He positioned himself against "the establishment" and "special interests," contrasting himself with what he described as career politicians. He will now face Democratic State Auditor Rob Sand in the general election, in a race nonpartisan election analysts have labeled a "toss up."