If Idaho Rep. Raul Labrador were to accept a position in the Trump Administration, it would trigger something that’s never happened before in Idaho history: A special election for a U.S. House seat, with no primary election first. “It’s a single special election, so everybody who wants to run for it just runs,” said Deputy Idaho Attorney General Brian Kane. “It’s a good old-fashioned donnybrook.”

Tim Hurst, Idaho chief deputy secretary of state, noted that if a U.S. senator leaves office mid-term, a replacement can be appointed, but that’s not true for U.S. representative. “Representatives need to be elected,” Hurst said, “so you have to have a special election.”

Under Idaho state law, that election would have to be set by the governor, who would specify its date in his proclamation. Though under the provisions of Idaho’s election consolidation law, there normally are only four dates per year on which elections can be held, that requirement’s waived for a special election for the U.S. House. Standard notice requirements for elections would apply: Polling places and hours would need to be published at least 12 days before the election.

Eric Ostermeier, a professor of political science at the University of Minnesota, reported in 2011 that after Nevada held a special election for its 2^nd Congressional District that year, Idaho became the only state that’s never held a special election for the U.S. House.

Idaho has had two vacancies in its 2^nd Congressional District seat in its history, but opted to allow them to stay vacant until the next regular election rather than call special elections, according to Ostermeier’s research. Those occurred in June of 1934 when then-Rep. Thomas Coffin, D-Idaho, died in office; and in November of 1946, when Republican Rep. Henry Dworshak resigned after being elected that month to the U.S. Senate.