ID-1 · House

The district, in brief

Idaho's 1st takes in the Idaho Panhandle and the western Boise area, on a map first used in 2022 that the facts do not mark as redrawn for 2026.

The incumbent is Republican Russ Fulcher, re-elected with 71.0% of the vote in 2024, who won his primary with 78.2% over Andy Briner (11.3%) and Joseph Morrison (10.5%). The Democratic nominee is Kaylee Peterson, an artisan jeweler and the party's nominee for this district in 2022 and 2024, who won her primary with 87.1% over Ken Brungardt. Sarah Zabel, an author and retired U.S. Air Force major general, is running as an independent, and Brendan Gomez, the Constitution Party's 2024 nominee, has filed paperwork. As of June 30, 2026 Fulcher had raised $662,615 with $244,700 on hand, Peterson $181,024 with $14,616 on hand, Zabel $81,497 with $24,473 on hand, and Gomez $0.

Every rater listed calls the seat R: Decision Desk HQ (July 14, 2026), the Cook Political Report (February 6, 2025), Inside Elections (March 7, 2025) and Sabato's Crystal Ball (April 10, 2025). The facts record a two-party margin for the Democrat of -47.23 in 2024 and -46.09 in 2022. Two district polls are recorded. Change Research, a Democratic firm (July 28–30, 2026, 606 LV), had Fulcher 48%, Peterson 27%, Zabel 5% and 18% undecided, and in a second version Fulcher 46%, Zabel 26%, 22% undecided. SurveyUSA (July 7–14, 2026, 480 LV) had Fulcher 45%, Peterson 35%, Zabel 6%, 14% undecided; its head-to-heads read Fulcher 44% to Peterson 39%, and Zabel 42% to Fulcher 39%.

A paragraph quoting a model forecast from the day this brief was written is omitted; the current forecast is at the top of this page.

The facts, each beside its sentence

Not in the source: The text gives no presidential results for the district.; No general-election ratings finer than 'R' are given.; The text lists no endorsements for any candidate.; The two district polls are on Wikipedia but the model's basis records no district polls.; The text does not say why the Change Research poll's second version omits Peterson.

Read from the district's section of Wikipedia's state page (CC BY-SA), archived as c3c77bd88867; written by claude-fable-5-1 (batch reader) on 2026-09-30 and checked mechanically: every quote occurs verbatim in the archived text, every number in the brief occurs in the inputs. No probability here is the reader's.

Who holds the seat now

Russ Fulcher (Republican), in this chamber since 2019, 4 terms. Committees: House Committee on Natural Resources; House Committee on Energy and Commerce.

From the congress-legislators dataset (CC0), archived as ae8cb9477c48. For a Senate race this lists both of the state's senators; the one whose term ends in the election year holds the seat on the ballot. For a House district redrawn for 2026 it is the member elected under the old lines with this number, who may be running elsewhere; the dossier above names who is running here.

How it has voted for president

A shift of 2.8 points toward the Republicans from 2016 to 2024. county returns placed on the current lines by 2020 block population; MEDSL county file (2016), an MIT-licensed county file (2020, checked against certified state results) and MEDSL precinct returns (2024). For a district split across counties this is an estimate, and where the state published the exact 2024 figure for these lines, that exact figure is the one the model uses.

Who are the voters?

Of about 627,941 adults 25 and over. In 2020 the district voted 30.4% Democratic (two-party) for president. With the same preferences and a 2022-style midterm turnout, it would vote 30.7% Democratic: the midterm electorate alone moves the margin 0.6 points toward Democrats. Group shares are estimated from how results vary across the state's census tracts (ecological inference, anchored to Pew's 2020 validated-voter figures) and calibrated to this district's actual 2020 vote; turnout is the Census survey's state rate by race and national rate by education, whose state samples carry margins of several points.

Not answered here: how each group will vote in 2026. These are 2020 preferences; this profile is description, not yet an input to the forecast.

The money

FEC bulk candidate summaries through July 08, 2026; $6,326 of independent expenditures for or against these candidates this cycle (FEC Schedule E, types 24E and 24A), which is the parties' and outside groups' own revealed view of whether this seat is in play.

The district in numbers

ACS 5-year 2023, the Census Bureau's own tabulation of this district (118th Congress lines). Unemployment is the BLS county series placed on the district by block population, not seasonally adjusted, so changes are same-month comparisons. Income, transfers and jobs are BEA county accounts placed the same way, compared with the average district. Every other figure is a named column of a named table in the Bureau's summary file, archived before it was read. This is what a reader knows about a district before looking at a poll; the model does not yet use it, and whether it should is a registered question.

Who is favoured, and by how much?

The 90% interval runs from -52.1 to -23.8 points, D-R. It is wide because this district has never been polled.

What is this built on?

A model trained on every contested House race 2012-2024 predicts this district's lean from its own record: presidential and House results on the current lines, incumbency, both candidates' prior offices, outside and party money before 1 October, demographics and public-assistance shares from the Census release before the election, local unemployment and income, and religious tradition. The national margin comes from presidential approval, the economy, the midterm penalty and the generic ballot corrected for its measured lean. Draws share national and state errors, so the seat total and this district come from the same simulation.

Not answered here: district polls, which are not yet folded in.

Why does the model say this?

Each figure is how far this district's predicted lean moves when that one feature is set to the typical value across 2026 districts, everything else held: 2024 presidential lean (R+44.7): 22.1 pts toward the Republican; 2024 House lean (R+44.5): 7.1 pts toward the Republican; 2022 House lean (R+43.7): 2.3 pts toward the Republican; asian share (1.1%): 1.0 pts toward the Republican; experience gap (-4 levels, D minus R): 0.7 pts toward the Republican.

How sure is it, and of what?

Total sd 8.57 points, made of the seat's own volatility 88%, correlated polling error 12%. The decomposition is stored with the forecast rather than reconstructed, so a probability whose dominant input is a placeholder is visibly that.

Not answered here: a nowcast. 'If ballots were cast today' needs something that observes today, and for a House district nothing does. Publishing the election-day figure under both labels would make one forecast look like two.

How was this number made?

Run 6f211e6f-2bdc-4dda-8f72-81fc628dab0b, house_district_prior/0.2.0, as of 2026-10-02. Promoted by a pre-registered gate: on 2016-2022 its Brier score was 0.036 against 0.049 for the previous method, and on a single 2024 run 0.023 against 0.032 (experiments/district_gate_result.md, with an independent review).