President Trump returned from his 12-day trip to Asia Tuesday night, with few major gaffes to answer for but few accomplishments to show for it, either—a fact he underscored with a strange “what I did on my fall vacation” speech Wednesday that failed to produce the “major” announcement he’d promised.

Trump headed out on his trip shortly after Special Counsel Robert Mueller’s first indictments and guilty plea, and the administration expressed some concern about that. “He worries about his ability to negotiate with various entities and how much he’s hamstrung by this,” a senior White House official told CNN, adding that Trump felt he’d be in a better position once the investigation was resolved.

Unfortunately for Trump, that could be months or years down the line. How will that affect his ability to conduct foreign policy? The record of previous presidents facing probes like Mueller’s shows that in fact they have turned to global affairs as a forum where they can make a difference and get things done even as domestic politics becomes a gridlocked nightmare for them. But they’ve relied on having a competent and carefully compartmentalized staff, and even so, the presence of an investigation can reduce what an administration can achieve.

“You can get work done, and you can make progress,” says David Gergen, who worked in the Nixon White House during Watergate and then in the Clinton White House during the early days of the Whitewater probe. “Investigations can weaken the White House, but you have to convince everybody else to keep working. I think it’s extremely important that everybody keep their bearings, that they’re not panicked, they’re not lashing out.”

But that sort of message control, and staff control, has been beyond the abilities of the Trump team since the start, making it even more challenging for them to achieve now. Moreover, the task of keeping an even keel starts with a firm hand on the helm—and this White House has struggled to cope with a president whose announcements often take his own staff by surprise. Nixon’s temper was legendary; Clinton, Gergen recalls, was prone to volcanic but short-lived outbursts, but he too was largely predictable. By contrast, “the present White House doesn’t have any sense of what the current president is going to say or do next.”

Nixon and Clinton were not alone in facing special-prosecutor investigations—Ronald Reagan did as well, for Iran-Contra. But that case is perhaps less useful as an analogue. For one, it concerned the conduct of foreign affairs, circumscribing the president from global moves in a different way. For another, although Reagan achieved few major things after the start of the Iran-Contra affair, he was also deep in his second term, a point at which presidents often achieve little anyway.

Both Nixon and Clinton viewed foreign affairs as a place where they could make a difference—both in the world and in their political standing—even as they lost traction domestically. Congress and the political press were consumed with their scandals, but overseas, the executive branch could work largely on its own.

It helped that both Nixon and Clinton invested a great deal of effort in foreign affairs. Nixon was the most traveled president up to that time, setting the precedent for the frequent-flying commander in chief, and had built genuine relationships with many of his counterparts abroad. In August 1973, a New York Times survey of foreign leaders found that “although foreign leaders and public figures now seem to take the Watergate scandal more seriously than they did a few months ago, the affair has not so far cut deeply into their widespread support for Mr. Nixon’s course in foreign policy,” and that “there has been no sign that Watergate has crippled any ongoing negotiations or otherwise set back normal diplomatic business.”

Speaking to the Miller Center at the University of Virginia in 2005, Clinton’s national-security adviser, Sandy Berger, recalled a feeling of solidarity during the Monica Lewinsky scandal.

“The president received a lot of support from foreign leaders during this period. They were somewhat mystified,” Berger said. “I think most foreign leaders are the subject of attack for some reason or another. Maybe there was a certain identification with the siege that Clinton was under and feeling that they, not necessarily for a similar kind of transgression, but that they had felt the brunt of an angry press and an angry Congress and could understand what Clinton was going through.”

Since Clinton was under investigation for most of his presidency, nearly everything he did in foreign affairs—from the Balkan wars to the Good Friday agreement—came under the cloud of Whitewater. Nixon’s list was shorter, but during Watergate his administration helped negotiate peace after the Yom Kippur War, brought about an end to the Arab oil embargo, and even conducted a triumphant foreign trip in the last months before his resignation.

Every political advantage brings a corresponding political weakness, and both Nixon and Clinton encountered the downside of turning abroad: Critics accused them of trying to use global affairs to distract from their political troubles. In October 1973, four days after the “Saturday Night Massacre,” and two weeks after Vice President Spiro Agnew’s resignation, Nixon ordered a global military alert, ostensibly in response to Soviet military movements, though critics viewed it as an attempt at distraction.

In August 1998, when Clinton ordered anti-terror air strikes in Sudan and Afghanistan, many observers compared it to the plot of the 1997 movie Wag the Dog and claimed they were misdirected, something Clinton and his aides have always denied. “People ask me how the Lewinsky thing affected me in foreign policy; it didn’t at all,” former Secretary of State Madeleine Albright told the Miller Center in 2006. “Except for people thinking that responding to the embassy bombings was Wag the Dog.”

Both Nixon and Clinton benefited from the ability to delegate, which created some separation between the scandals and their international relations, and strong staff work. As early as April 1973, Nixon was complaining about how much time Watergate consumed. “Well, I’ll hear about it a lot but I’ve got to run the country,” he said, in a conversation captured by his infamous taping system. After H.R. Haldeman’s resignation, Nixon hired General Al Haig to be his chief of staff, and Haig is credited with bringing order to the White House. Nixon also had in Secretary of State Henry Kissinger an aide who could (for good or ill) basically run the nation’s foreign-policy apparatus without much input from the president. While Kissinger attributed many decisions to the president, Stephen Stathis of the Congressional Research Service wrote that few observers believed that anyone other than Kissinger was running the show.

Albright reported that Clinton, in contrast, remained heavily involved in foreign-affairs issues, even at the height of his impeachment, and was able to compartmentalize his presidential work from his legal troubles. “I think that some of the domestic staff probably had times when he would scream at them and stuff,” she told the Miller Center. “I never had that. I saw him a lot, but I didn’t go in there every single day because I was on the road.”

Even so, these diplomats found that domestic scandals did sometimes disadvantage them. Kissinger later admitted that in the closing months of Nixon’s presidency, foreign leaders were wary of making agreements with the U.S. They could see that Nixon was likely headed for either conviction or resignation, making him a lame duck.

“Every negotiation was getting more and more difficult because it involved the question of whether we could, in fact, carry out what we were negotiating,” Kissinger said. “Secondly, we were not in a position to press matters that might involve serious domestic disputes.” This was felt particularly in the Strategic Arms Limitations Talks II, where Kissinger said the U.S. negotiating position was undercut. (A treaty was eventually signed, in 1979, but never entered effect, because the U.S. pulled out following the Soviet invasion of Afghanistan.)

If Trump wishes to emulate the successes of his predecessors, he has his work cut out for him.

First, while Trump’s White House shares some of the same weaknesses that plagued both Nixon and Clinton’s West Wings—chaos, backstabbing, factionalism—the current administration has taken these tendencies to new levels. Trump struggled to get much done even before the Mueller probe, though he has been dealing with implications of the Russia matter since he took office. Gergen said the current White House chief of staff was making strides, comparing him to Haig—“the John Kelly of his time”—but the West Wing remains in a state of nearly constant turnover. Investigations often breed greater paranoia and paralysis among administration staff who are worried about legal liability.

Unlike Nixon and Clinton, Trump doesn’t seem to have strong rapport with foreign leaders. He has gotten along well with France’s Emmanuel Macron, Japan’s Shinzo Abe, and Canada’s Justin Trudeau, but has not yet forged close, ongoing relationships with them; all three have material differences with him on matters of policy. He has not fared as well with Theresa May, who as British prime minister leads America’s closest ally, and his relations with German Chancellor Angela Merkel have been downright icy. A personal bond with Chinese President Xi Jinping has so far translated into little concrete action, even on North Korea, and Trump’s good relationships with leaders in Saudi Arabia and the Philippines show little prospect for producing major global breakthroughs.

Trump also doesn’t have a strong staff in place that can keep their heads down and work on their jobs, nor lieutenants he can trust. He has repeatedly undercut Secretary of State Rex Tillerson, making it very clear to foreign leaders that Tillerson does not speak for the president. Meanwhile, the lower ranks of his administration remain empty. This is especially true at the State Department, and when Laura Ingraham asked Trump about it earlier this month, he was dismissive.

“Let me tell you, the one that matters is me,” he said. “I’m the only one that matters, because when it comes to it, that’s what the policy is going to be. You’ve seen that, you’ve seen it strongly.”

The disinclination to delegate dates back to his business days, when he could work with a lean staff and still get a great deal done, though as his struggles in office indicate, the presidency doesn’t work that way. While the Mueller probe certainly doesn’t help, the failure to pick and to empower aides may hamstring Trump’s foreign policy more than any investigation ever could.