Idaho’s Costliest Legislative Primary Pits Sen. Jim Guthrie Against Challenger David Worley in District 28
A state Senate primary race in southeastern Idaho has become the most expensive legislative primary matchup of the 2026 election cycle, with combined spending by candidates and outside groups topping $500,000.
The contest between incumbent Sen. Jim Guthrie, R-McCammon, and challenger David Worley in District 28 has drawn $503,652 in total spending as of mid-May. That figure includes $128,545 spent by the two campaigns directly and $375,107 in political action committee expenditures.
Guthrie, seeking his ninth term in the Idaho Legislature, represents a district stretching from Preston to American Falls and into rural areas near Pocatello. PACs have spent $237,205 connected to his race, with roughly 89% of that money spent in his favor. His outside support comes largely from business-aligned groups, including the Idaho Prosperity Fund PAC, which is connected to the Idaho Association of Commerce and Industry, and the Idaho Liberty PAC, which has received contributions from St. Luke’s Health System and Micron Technology. The WinAg PAC and the PAC for Public Lands have also backed the longtime lawmaker.
Two PACs tied to out-of-state funding have moved against Guthrie. Make Liberty Win, associated with Young Americans for Liberty, has spent more than $23,000 opposing him. The Citizens Alliance of Idaho has spent a smaller amount in opposition.
PAC Money Splits on Worley
Outside spending on Worley’s behalf amounts to roughly $137,902, with the money evenly split between support and opposition. Make Liberty Win and the Citizens Alliance of Idaho, which oppose Guthrie, are backing Worley. The most notable pro-Worley spender is the 36-18-1 PAC, funded by Rep. Jordan Redman, R-Coeur d’Alene, which has put more than $22,000 behind the challenger.
On the other side, the Idaho Liberty PAC has directed more than $35,000 against Worley, and Defend and Protect Idaho has spent over $20,000 in opposition.
Constitutional Officers Weigh In
The race has drawn unusually high-profile attention from statewide elected officials. Attorney General Raul Labrador has endorsed Worley. On the other side of that ledger, Gov. Brad Little, Lt. Gov. Scott Bedke, Superintendent of Public Instruction Debbie Critchfield, Secretary of State Phil McGrane, and Controller Brandon Woolf have all lined up behind Guthrie, a notable show of institutional support for the incumbent.
North Idaho Rematch Not Far Behind
The second most expensive primary in the state this cycle is playing out closer to home for North Idaho readers. Sen. Jim Woodward of Sagle faces a rematch against Scott Herndon, also from Sagle, in what has become a $267,790 contest. PACs account for $134,570 of that total, with the two campaigns spending another $133,220 between them.
Herndon, running to the right of Woodward on issues including a proposal to eliminate property taxes, has drawn support from Redman’s 36-18-1 PAC and the Idaho Summit PAC. Rep. Josh Tanner, R-Eagle, serves as treasurer of that PAC, with Redman as chair.
Woodward has received outside support from Defend and Protect Idaho, which describes its mission as combating political extremism in Idaho, and from the PAC for Public Lands.
The May 19 primary is less than a week away, and additional PAC disclosures are expected before voting begins. Full spending totals for both races won’t be available until June. North Idaho Republican will continue following both contests as results come in.
For context on the broader state budget picture heading into this election season, see our earlier coverage on Idaho’s April revenue collections and the projected year-end surplus.
North Idaho Republican Staff
