Secretary of the Interior Ryan Zinke has officially resigned, part of a wave of high-profile departures from the Trump administration after the midterm elections.

It's been a high honor to serve @POTUS & the American People as @Interior Secretary. We've restored public lands “for the benefit & enjoyment of the people,” improved public access & shall never be held hostage again for our energy needs. God bless America & those who defend her. pic.twitter.com/JXzVmrpDTg — Secretary Ryan Zinke (@SecretaryZinke) January 2, 2019

President Donald Trump first announced Zinke’s departure in December with a pair of tweets. Zinke’s deputy David Bernhardt, a former oil executive, will take over the agency until a replacement is named by the White House and confirmed by the Senate.

In office, Zinke dutifully advanced Trump’s promise to boost coal, oil, and natural gas production ever since he rode in to work on a horse named Tonto in March 2017. He has presided over the largest rollbacks in federal land protections in US history and opened up unprecedented swaths of coastal waters for drilling.

Some of Trump’s other Cabinet picks were openly disdainful of their agencies. Former Environmental Protection Agency Administrator Scott Pruitt, for example, sued the EPA 14 times as Oklahoma’s attorney general.

But Zinke, a former Navy SEAL and Montana Congress member, billed himself as an outdoorsman who believed in protecting public lands. He also racked up a long list of indiscretions, triggering at least 18 federal inquiries, probes, and investigations into his conduct, according to Citizens for Responsibility and Ethics in Washington.

Yet he managed to stay on Trump’s good side, avoiding much of the negative attention that seemed to follow Pruitt everywhere during his last days in office.

Zinke has also been one of the more impactful Cabinet members, making decisions that will have lasting consequences for energy development and the environment.

However, Democrats are now the majority in the House, taking over committees with oversight of the Interior Department and vowing to launch more investigations into Zinke. So the time seems to be ripe for him to jump out of the crosshairs, but not before taking a parting shot at Rep. Raúl Grijalva (D-AZ), the incoming chair of the House Committee on Natural Resources.

Ryan Zinke racked up a long list of scandals

In his nearly two years in office, Zinke built up a distinct public persona. He rode a horse to his first day of work, displayed his knife collection at his office until security staff asked him to take it down, minted his own challenge coin, and had his office fly a flag whenever he was in the building.

But Zinke began steadily accumulating ethics troubles. These include his $12,375 charter flight to see a hockey team owned by a donor, his decision to block two Native tribes in Connecticut from opening a casino after an intense lobbying effort from Nevada Republicans, and allegations of retaliation against an agency policy expert who reported on the impacts of climate change on Native Alaskans.

His involvement with a land deal with the chair of oil services firm Halliburton, David Lesar, was referred by the Interior Department’s Inspector General to the Department of Justice. This means federal prosecutors are weighing whether to pursue a criminal investigation.

A tiny company based in his hometown of Whitefish, Montana, was also awarded a multimillion-dollar contract to rebuild Puerto Rico’s devastated power grid after Hurricane Maria despite having just two full-time employees at the time and little experience in disaster response. The deal triggered an FBI investigation. Zinke has denied any involvement in the deal, though his son once had a summer job at a Whitefish Energy construction site.

Zinke also reportedly threatened Alaska Sen. Lisa Murkowski after she voted against a Republican effort to repeal the Affordable Care Act. However, the Inspector General had to close the investigation into the allegations because the Interior Department didn’t cooperate.

Then there were the bizarre stories, like reports that a house guest of his impersonated him and called the US Park Police, which fall under the Interior Department, to respond to dispute with a neighbor over a parking spot.

Zinke was an ideologue who served fossil fuel interests

The Department of the Interior manages federal lands, natural resources, and administers programs for Native Americans. This includes operating national parks, leasing drilling rights, and preserving wildlife habitats.

Under the Trump administration, the department made a priority of encouraging fossil fuel development on federal lands in pursuit of “energy dominance.” During his time in office, Zinke made it abundantly clear whom he wanted to protect and whom he saw as the villains. He told the Louisiana Oil and Gas Association that “our government should work for you,” a remark that earned him a standing ovation.

On the other hand, he blamed California’s massive wildfires on “environmental terrorist groups” and waffled as to whether climate change played a role in the blazes.

One of Zinke’s first actions in office was to lift an Obama-era moratorium on new coal leasing. In January 2018, the Interior Department proposed opening up nearly all US coastal waters to offshore oil and gas drilling, reversing the protected status of these regions and teeing up the largest mineral rights lease sale in US history.

These actions were part of a coordinated suite of policies to boost oil and gas drilling at the behest of the industry, as Vox’s Emily Stewart wrote:

The Interior Department under Secretary Ryan Zinke has offered so much land in auctions that most haven’t had any bidders at all. The department last year sent out a memorandum to field offices telling them to “alleviate unnecessary impediments and burdens” and to “expedite the offering of lands for lease.” In other words, to make leases for drilling easier and faster to get.

Zinke was also happy to align himself with Trump’s other priorities like immigration.

4,000% increase in arrests of illegal aliens on @Interior borderlands under @realDonaldTrump administration. https://t.co/dOnFdnQJYb — Secretary Ryan Zinke (@SecretaryZinke) November 9, 2018

Zinke worked to drastically weaken environmental protections

The Trump administration has also made a point of undoing environmental regulations, and Zinke has presided over some of its most impactful rollbacks.

Zinke recommended and the White House approved shrinking the size of 10 national monuments, areas in federal lands protected from development. The list included the Bears Ears and Grand Staircase-Escalante monuments in Utah, together rolling back protections on 2 million acres of federal lands. The move marked the largest loss of federal land protection in US history.

Emails showed that facilitating oil drilling was a key reason behind the Interior Department’s decision to undo federal protections.

The White House also rolled back regulations on offshore drilling that were put in place by the Bureau of Ocean Energy Management at the Interior Department after the Deepwater Horizon oil spill killed 11 workers and sent 4.9 million barrels of crude oil into the Gulf of Mexico in 2010.

In addition, the Interior Department loosened restrictions on methane produced from oil and gas drilling on federal lands.

Endangered species protections were also eroded. The US Fish and Wildlife Service at the Interior Department this summer proposed weaker rules for adding animals and plants to the endangered species list as well as making the government weigh the economic costs of protecting wildlife under the Endangered Species Act. Many organisms in danger of dying out forever live on public lands, and environmental activists have long used the Endangered Species Act to block mining and development in vulnerable habitats.

Many of the big policy changes Zinke has made aren’t set in stone. Outdoor recreation groups, conservationists, and Native American tribes have already sued to block many of these rollbacks, and in some cases, courts have ruled against Zinke. But the changes that do survive will serve to increase fossil fuel emissions and shrink pristine natural environments.

What’s next for Zinke remains uncertain. Politico reported in November that he reached out to Fox News to look into becoming a contributor for the network, but a spokesperson denied the story in comments to the Hill.