Idaho Code § 34-714
(1) Vacancies that occur before the primary election in the slate of candidates of any political party because of the death, disqualification for any reason, or withdrawal from the nomination process by the candidate shall be filled in the following manner if there is only one (1) candidate declared for that particular office:
(c) By the state central committee if the vacancy occurs for a federal or state office.
The county and legislative district central committee shall fill the vacancy within fifteen (15) days from the date the vacancy occurred. The state central committee shall fill the vacancy within thirty (30) days from the date the vacancy occurred, but no later than 5:00 p.m. on the eighth Friday before the primary election.
Any political party candidate so appointed by the proper central committee must, in order to have his name on the primary ballot, file a declaration of candidacy and pay the required filing fee no later than 5:00 p.m. on the eighth Friday before the primary election.
[34-714, added 1970, ch. 140, sec. 118, p. 351; am. 1971 (E.S.), ch. 9, sec. 7, p. 20; am. 1975, ch. 21, sec. 3, p. 30; am. 1976, ch. 60, sec. 10, p. 205; am. 1989, ch. 70, sec. 3, p. 112; am. 1996, ch. 28, sec. 26, p. 77; am. 1999, ch. 222, sec. 1, p. 588; am. 2025, ch. 113, sec. 14, p. 607.]