The Interior Department oversees 500 million acres of federal public land — national parks, wildlife refuges, offshore drilling areas, and mineral leasing. It is one of the most consequential regulatory positions in the federal government for the energy and mining industries. Zinke came in with a stated commitment to expanding energy production on public lands and reducing what he called regulatory overreach. What he also brought was a pattern of conduct that generated investigation after investigation.
The Travel Abuses.
Zinke used charter flights at taxpayer expense for travel that could have been accomplished on commercial airlines at a fraction of the cost. A review by the Interior Department's Inspector General found multiple instances where Zinke's travel arrangements were problematic or improper. In one case, a charter flight from Las Vegas to his hometown in Montana cost approximately $12,000. In another, he used a government helicopter to commute to a horseback riding event with Vice President Pence — arriving via government transport at a political event. The IG found his conduct "may have violated" federal travel regulations.
The Halliburton Deal.
While serving as Interior Secretary, Zinke was involved in a real estate development project in his hometown of Whitefish, Montana with David Lesar, the chairman of Halliburton — a major energy company with significant interests before the Interior Department. The project involved developing land adjacent to Zinke's property. The arrangement raised conflict of interest concerns given that Halliburton was subject to Interior Department decisions on drilling leases and energy policy. The Interior Department IG referred the matter to the Justice Department for potential investigation.
The Monument Boundaries.
Zinke led the review of national monuments that resulted in Trump's reduction of Bears Ears and Grand Staircase-Escalante. Internal documents obtained by journalists showed that the recommended boundary changes for Grand Staircase-Escalante corresponded closely to areas where a Canadian mining company held coal leases — suggesting the boundary reductions were drawn to benefit specific extraction interests rather than for the public interest reasons stated publicly. Zinke denied any improper influence.
The Interior Department IG travel report was publicly released and covered by the Washington Post and New York Times. The Halliburton/Lesar connection was reported by The Guardian and confirmed by Interior IG referral to DOJ. The monument boundary/mining correlation was documented by The Guardian and The New York Times using internal documents. Zinke's resignation was announced December 15, 2018, effective January 2, 2019.
Zinke was never charged with any crime. He returned to Montana, ran for Congress, and won. He now serves in the House of Representatives. In 2023, the House Ethics Committee investigated him over allegations related to his conduct as Interior Secretary and a subsequent business venture. The committee found sufficient evidence to warrant further review. Zinke denied wrongdoing.
- Interior Department Inspector General reports — travel violations; helicopter use; publicly available.
- The Guardian, 2017–2018 — Halliburton/Lesar real estate deal; monument boundary/mining correlation reporting with internal documents.
- New York Times, 2017–2018 — contemporaneous coverage of Zinke investigations and monument review.
- Zinke resignation announcement — December 15, 2018; White House statement.
- House Ethics Committee, 2023 — investigation referral re: Zinke conduct; Committee statement.