Immigration enforcement emerged as one of the defining fault lines in Idaho’s May 19 Republican primary election, driving several high-profile incumbent defeats and shaping candidate platforms across multiple legislative districts.

Nine Incumbents Unseated

When the dust settled from the May primary, nine sitting legislators had lost their seats to primary challengers. Five of those defeats involved members of a bloc of hardline conservatives known as the “Gang of Eight.” In contrast, two incumbent Republicans in North Idaho who were seen as more moderate lost their primaries to candidates positioned further right — underscoring that the ideological pressures ran in different directions depending on the district.

Boise State University political science professor Jaclyn Kettler noted the pattern: “In some areas of the state we saw more hardline conservatives, especially on issues of immigration enforcement, be successful.”

All 105 seats in the Idaho Legislature are on the ballot every two years, making the primary a significant reshaping moment for the body’s composition ahead of the November 3 general election.

A High-Profile Senate Defeat

Among the notable losses was Twin Falls-area Sen. Glenneda Zuiderveld, a Gang of Eight member representing Senate District 24, who was defeated by Brent Reinke — a former Twin Falls County commissioner who previously served as director of the Idaho Department of Correction. Reports from multiple news organizations had linked Zuiderveld’s husband’s dairy business to fallout over her immigration enforcement positions, with several dairies reportedly severing ties over the controversy.

The Senate District 28 race offered a different outcome. Sen. Jim Guthrie, who chairs the Senate State Affairs Committee — a panel that typically handles immigration-related legislation — held off a primary challenger who had listed upholding immigration law as his top campaign priority. Reps. Rick Cheatum and Dan Garner also emerged from their District 28 races, with Garner running without opposition.

Stalled Bills and Employer Verification

The primary results unfolded against a backdrop of unfinished legislative business. Several immigration enforcement measures failed to advance during the 2026 legislative session, leaving supporters looking toward the next session for another attempt.

Coeur d’Alene Republican Rep. Jordan Redman has pursued legislation for three consecutive years that would require Idaho employers to use the federal E-Verify system to confirm workers’ legal eligibility. The effort has yet to reach the governor’s desk. Redman expressed measured optimism in the wake of the primary results, saying he is “hopeful that we’ll be able to get more of this immigration legislation through this upcoming year.”

The employer verification push has met organized resistance from Idaho’s agricultural sector. The Idaho Dairymen’s Association has opposed measures that would penalize employers for hiring undocumented workers, arguing that the industry relies heavily on foreign-born labor and lacks access to the H-2A agricultural guest worker visa program that covers some other farm sectors. That tension — between hardline enforcement advocates and industries dependent on immigrant labor — played out visibly in several primary contests, including the Zuiderveld race. An audit of the Ada County primary confirmed the accuracy of the May election results, adding confidence to the statewide outcome.

Looking Ahead to November

With the primary complete, candidates who survived or won their way through the Republican field will face general election opponents on November 3. The ideological sorting that took place in May — with some moderate incumbents ousted and some hardliners also losing ground — leaves the Legislature’s composition in flux heading into the next session.

The immigration enforcement debate is unlikely to fade before then. Idaho Republican Party Chair Dorothy Moon, who has pushed conservative priorities throughout her tenure, has signaled continued attention to immigration-related issues within the party. How the newly shaped legislative caucus handles employer verification and related measures when the next session convenes will be closely watched by both enforcement advocates and the agricultural industry that has resisted parts of that agenda.