One week after the election, President-elect Trump’s White House staff is still being formed, but one familiar name has already surfaced: Peter Thiel. The PayPal co-founder has become one of the most controversial figures in Silicon Valley, thanks to his unusual and often alarming political views, as well as a recently revealed crusade to bankrupt Gawker Media through frivolous litigation, waged secretly over the course of a decade.

Most recently, Thiel caused a stir in tech circles with his outspoken support for Trump, expressed through a $1.25 million donation to the campaign as it hit a low point in October. With Trump’s transition team now assembling the incoming cabinet — and Thiel playing an active role in that transition — the candidate seems poised to return the favor.

Thiel would come to government service with a web of conflicts

But putting Thiel in a White House position would be more complicated than it sounds — and could cost the eccentric billionaire more than he’s willing to give up. Thiel would be coming to government service with a web of conflicts from the private sector, including dozens of board memberships and early-stage investments in companies like SpaceX and Airbnb. He’s also the chairman, co-founder, and primary shareholder of Palantir, a secretive data-mining firm with tens of millions of dollars in government contracts. The nature of venture capital makes it unusually difficult to sever those ties cleanly. That doesn’t mean a Thiel appointment would be impossible — but it would raise difficult conflict-of-interest questions, and it’s anyone’s guess how Trump would respond.

The most immediate problem is Thiel’s membership on a number of boards of directors, particularly at Facebook, Zenefits, and as chairman at Palantir. Those directorships are a major part of his power within the tech world: they allow Thiel to influence investments and strategy at some of the industry’s most powerful companies. But from a government ethics perspective, each one is a conflict of interest. The law clearly prohibits federal employees over a certain pay grade from outside employment — and Thiel will most certainly clear that pay grade. Another law forbids participating in any decision with a predictable effect on the finances of an organization where you sit on the board, even if the board position is unpaid. (Notably, both the president and vice president are exempted from those laws.)

If you work for the White House, you can’t work anywhere else

The result, for ethics lawyers, is fairly cut and dried. “If an individual is appointed to a full-time executive branch position, they are not going to be permitted to serve on the board of a for-profit corporation at the same time,” says Wiley Rein’s Robert L. Walker, who served as chief counsel for the House and Senate ethics committees. Even though Thiel only meets with each board every few months, the government still views each directorship as a standalone job. As long as you have a full-time job at the White House, you can’t have a full-time job anywhere else.

But while quitting those directorships would be the first step, it wouldn’t completely dispel Thiel’s potential conflicts of interest. As of the company’s most recent funding round, Thiel is also the majority shareholder in Palantir, a data-mining firm with deep ties to many of the government’s intelligence agencies. Palantir contracted over $80 million in work with the federal government last year, and recently won a bitter lawsuit with the Pentagon for the right to solicit even more work. Under the law, Thiel would be required to avoid any decision that might have a predictable effect on Palantir’s finances — but given Palantir’s wide range of interests, that would be very hard to do.

Through Founders Fund, Thiel also holds significant stakes in SpaceX, Airbnb, and Lyft, all of which are significantly impacted by government policy. However Thiel serves in the White House, it’s hard to imagine it won’t somehow intersect with space flight privatization or the gig economy.

The simplest solution would be to divest his holdings and enter government with a clean financial slate. But because all of the companies are privately held, divesting is not as easy as putting in a sell order. There’s no public market for Palantir stock, so Thiel would have to sell his stake piece by piece — a process that’s rare but not unprecedented. With Thiel’s stake in Palantir valued as high as $10 billion, those deals can take years to arrange and would cause lasting instability within the company. So far, there are no rumblings of any such activity at Palantir.

Divesting from Founders Fund would be slightly simpler, and presumably there would be plenty of outside investors willing to buy his stake in the firm — but with Airbnb and SpaceX both approaching rumored IPOs, it could still cost Thiel a significant payday.

If Trump and Thiel decide they just don’t care about ethics laws, there’s not much anyone can do

It’s difficult to say exactly how Thiel could navigate that conflict without divesting, given the broad reach of his investments — but there’s also a real possibility that he might not navigate it at all. As a candidate, Trump often gleefully flouted political norms like releasing tax returns and health records, and it’s entirely possible he might treat the ethics of executive appointments with a similar disregard.

If he does, there would be no immediate enforcer in the government to stop him. The first line of defense is the transition team’s counsel (essentially, Trump’s lawyer), who vets each appointment internally for potential conflicts. The next step is to get recommendations from the Office of General Ethics, an independent, non-partisan agency in the executive branch, which gives a full report for each incoming appointee. But crucially, the Office of General Ethics is still only advising the incoming administration on how to steer clear of various ethics laws. If Trump and Thiel decide they just don’t care about ethics laws, there’s not much the Office of General Ethics can do.

“We listened to the lawyers”

From there, the ethics question would become a special case of a more general problem: how do you stop someone in government from breaking the law? The federal laws on conflicts-of-interest are quite clear, but they can only be prosecuted by the Department of Justice. We still don’t know who Trump will appoint to run the Department of Justice, but they may not be interested in prosecuting internal ethics violations. That doesn’t mean there would be no consequences to flouting the law — opponents could certainly use the issue to inflict political damage — but it’s entirely a question of when the president decides to give in. Given what we’ve seen from Trump as a candidate, that could be an unpredictable process.

In fact, adhering to those recommendations was one of Obama’s main suggestions for Trump as he left office. “We listened to the lawyers,” Obama said in a press conference on Monday, “and we had a strong White House Counsel’s Office. We had a strong Ethics Office… And one of my suggestions to the incoming president is that he take that part of the job seriously as well.” If he doesn’t, the implication goes, he could take a lot of political damage.

Trump’s first week of transition has been chaotic, and we still know very little about what he hopes to achieve with his new cabinet. We know even less about what Thiel wants. He wants to wield power in the new administration, to be sure, but does he want it enough to give up his roles at Palantir, Facebook, and Founders Fund? Is he actually interested in giving up venture capital for the less glamorous demands of a government job? The most likely path forward might be for Thiel to stay behind the scenes, advising the president and his staff outside the bounds of a formal role. Still, for anyone concerned about Thiel’s politics — whether it’s libel laws, higher education, or gender politics — that may not be a comforting thought.