Mr. Riggs said the local party has been increasingly taken over by zealots motivated by a desire to limit the influence of government, sometimes at the expense of the traditional Republican goals of promoting business and growth. Many of the new activists, he said, express a willingness to fight the U.S. government, with arms if necessary.
One of the growing powers in the region is the John Birch Society, which dominated the far right in the 1960s and 1970s by opposing the civil rights movement and equal rights for women while embracing conspiratorial notions about communist infiltration of the federal government. The group was purged from the conservative movement decades ago but has found a renewed foothold in places like the Idaho panhandle.
Ms. McGeachin, the lieutenant governor, has angled to seize the support of that wing of the party. A few weeks before she traveled to the gymnasium event in northern Idaho, she made a video address to the America First Political Action Conference, an event organized by a prominent white nationalist, Nick Fuentes. In an interview, Ms. McGeachin said she had no regrets about doing so.