There is a long, colorful history of corruption involving the Interior Department.

Fraudulent deals implicating the federal government’s public land and resources management agency were frequent in the 19th century. Back in the 1920s, President Warren Harding’s administration used the agency to strike cozy, bribe-fueled deals granting oil companies access to the Navy’s petroleum reserves at three locations, including a Wyoming site known as Teapot Dome.

The “Teapot Dome Scandal” that emerged from all of that was the high-water mark in federal corruption investigations until Watergate came along in the 1970s. The gloriously disturbing and revealing Jack Abramoff lobbying scandal of the mid-2000s involved the Interior Department. A smaller scandal surfaced shortly after that when a deputy assistant secretary at the agency resigned her post after it was revealed that she altered scientific reports and disclosed confidential government information to benefit interest groups and private landowners. A separate scandal involving bribes, sex, cocaine and insider deals at the Interior Department emerged in 2008.

Now, of course, we have Interior Secretary Ryan Zinke’s travails. According to a Washington Post report published last Tuesday, the Interior Department’s own internal watchdog, the Office of Inspector General, has referred one of multiple examinations of Zinke’s conduct to the Justice Department for further investigation.

The agency’s deputy inspector general, Mary L. Kendall, is overseeing the Zinke probes. According to The Post, it’s unclear which of those inquiries were referred to the Justice Department. But the fact that one of them has landed there is noteworthy because it means that Zinke might face criminal charges. The Post quoted a senior White House official as saying that the Justice Department will look into whether Zinke “used his office to help himself.”

The Justice Department investigation of Zinke lands at a vulnerable moment for President Trump’s administration. The midterm elections this week could force a changing of the guard in Congress and give Democrats control of powerful federal oversight committees. Those bodies might choose to issue subpoenas and hold hearings to take the White House to task on various ethics problems and financial conflicts of interest that have hung over the president and a number of his Cabinet members and senior advisers – including his daughter, Ivanka Trump; his son-in-law, Jared Kushner; Secretary of Commerce Wilbur Ross and Secretary of Education Betsy DeVos. (And don’t forget former Health and Human Services Secretary Tom Price and former Environmental Protection Agency Administrator Scott Pruitt‘s scandal-fueled departures from the administration.)

Zinke’s new problems throw all of this into sharp relief.

Among other probes, Kendall is examining Zinke’s role in a Montana land development backed by David J. Lesar, the chairman of the energy services giant, Halliburton Co., The Post noted. The Post also said that Kendall is exploring Zinke’s decision to prevent two Native American tribes from running a Connecticut casino.

The Inspector General’s Office has already issued a report disclosing that the Interior Department’s ethics officials were troubled by Zinke’s decision to allow his wife to travel with him – and that Zinke told his staff to explore the possibility of lining up a volunteer job for his wife at the Interior Department so he wouldn’t have to pay for her travel. (Zinke has denied that that was the reason he was trying to arrange the job for his spouse.)

The same report also found that Zinke charged taxpayers $25,000 for a security detail to escort the Zinkes while on a vacation to Turkey and Greece. The report also disclosed that Zinke had invited two of his former political fundraisers to join him on an official trip at government expense and didn’t tell Interior Department lawyers that they were fundraisers. Meanwhile, the agency recently had to backtrack on a move that would have placed a Trump political appointee at the top of the agency’s Inspector General’s Office – the very office investigating Zinke.

Zinke, a former Navy SEAL and Montana congressman, has been at the center of myriad controversies involving his personal ethics and practices during his tenure at the Interior Department. That stockpile of inquiries – at least 18 in all – makes Zinke the most frequently investigated interior secretary in recent years, according to the Center for Western Priorities, a nonprofit conservation and advocacy organization.

A relatively unknown congressman at the time, Zinke was handpicked for his Interior Department post by the president’s oldest child, Donald Jr., who was a novice in governmental affairs. The younger Trump’s involvement came at a time when the Trumps were telling critics that the president’s children would focus on running the Trump Organization and not busy themselves with White House matters.

Critiques of his ethics and federal probes into how he ran things at the Interior Department may have left Zinke confused. After all, he serves a president who flouts conflicts-of-interest standards and he oversees a federal agency operating under a revised mission statement. An earlier statement directed the Interior Department to recognize that it “protects and manages the Nation’s natural resources and cultural heritage.” Trump reportedly had that language altered to ensure that the Interior Department also pursued a new goal – “to supply the energy to power our future.”

Perhaps whenever Zinke did anything construed as bending the rules in favor of energy companies, he was just following a presidential directive for the Interior Department to “supply the energy.” And that would have been something Zinke could get behind.

“I look forward to making the Department of the Interior and America great again,” he once promised.