For scholars studying the effects of presidential leadership on U.S. foreign policy, Donald Trump’s surprise victory in 2016 has offered quite the test. What does it mean for the United States to elect a leader with no experience in government, little knowledge of foreign policy, and an explicit disdain for expertise?

After a year in office, Trump has confirmed a lot of what we knew about how leaders matter: he has held firm to the few beliefs he brought with him to office, demonstrated the importance of substantive knowledge (or lack thereof) for decision-making, and shown why advisers cannot substitute for experienced leadership. In other ways, he has proven a surprise, principally by failing to appoint people who could help him get what he wants. And as the world faces at least another three years of Trump, there are few reasons to think his behavior will change in the future.

GREAT MAN THEORY

International relations scholars long believed that leaders do not matter much—states will act how they act, regardless of who is at the helm. The political scientist Kenneth Waltz, for instance, has argued that the constraints of the international system, not individuals or domestic politics, determine the actions of states.

More recently, however, that view has begun to change. Long before Trump’s election, scholars had assembled a wealth of new evidence about how individual leaders influence their countries’ behavior. One major finding is that leaders’ background experiences and beliefs—formed long before they arrive in office—shape how they make decisions, from taking in and processing information to deliberating with advisers and, ultimately, deciding on a course of action. What we see when leaders enter office is essentially what we’ll get, at least for the first few years.

Three insights from this body of scholarship stand out in particular. First, leaders’ beliefs are “sticky,” meaning that they are formed before leaders enter office and tend not to change much over time. As former U.S. Secretary of State Henry Kissinger wrote in his memoirs, “The convictions that leaders have formed before reaching high office are the intellectual capital they will consume as long as they continue in office.” Although such stickiness is sometimes seen as a defect, fixed beliefs are, as the political scientist Robert Jervis has argued, necessary guides that help decision-makers grapple with a complex world. We should not want our leaders’ beliefs to change too rapidly—sticky beliefs are a feature, not a bug.

Trump, his wife, Melania, and their son Barron arrive in West Palm Beach, January 2018. Kevin Lamarque / Reuters

The second insight is that substantive knowledge matters—it is important for leaders to be informed about the world—and there are no shortcuts for acquiring that knowledge on the job. Research on expertise shows that it is “domain-specific,” meaning that it does not translate from one topic or issue area to another; even chess masters are humbled by the random placement of pieces on a board. Little wonder, then, that business experience does not translate into foreign policy acumen.

Third, although advisers and bureaucratic appointments are crucial, they are no substitute for a leader with direct foreign policy expertise. Inexperienced presidents often make the case that advisers can fill the gaps in their own knowledge or tutor them on the job. During the 2000 presidential campaign, for example, George W. Bush emphasized that he would be “surrounded by good, strong, capable, smart people.”

But as my own recent work has shown, it matters a great deal whether a president has as much knowledge of foreign policy as his advisers. Experienced leaders provide better oversight of foreign policy decision-making because they are more likely to ask hard questions, spot poor planning, or recognize unrealistic proposals. Their reputation for expertise can enhance oversight indirectly, since subordinates know that their boss will check their work. Experienced presidents are also better able to draw on diverse sources of advice.

In Bush’s case, his inexperience empowered advisers such as Vice President Dick Cheney to act without oversight, leading to poor planning for the Iraq war and its aftermath. By contrast, Bush’s father, former President George H. W. Bush, relied on many of the same advisers, including Cheney (who was then secretary of defense), to plan the successful Gulf War in 1991. An important difference was that the older Bush, a former vice president, UN ambassador, and director of the CIA, had deep foreign policy experience that prompted his team to question and revise war plans before they even made it to the Oval Office.

A NORMAL PRESIDENT?

Despite the near-continuous drama of the last 12 months, Trump’s first year in office has confirmed much of what we know about how leaders affect foreign policy. That does not mean that Trump has played by the old rules—he has not. But he is essentially the president hired on November 8, 2016: a man with a few fixed beliefs and little substantive knowledge. And his actions as president have tended to confirm the three insights noted above.

Despite the near-continuous drama of the last 12 months, Trump’s first year in office has confirmed much of what we know about how leaders affect foreign policy.

First, although Trump is often accused of lacking any fixed beliefs, he has several sticky views that were visible before the election. Exactly one year before Trump’s inauguration, the journalist Thomas Wright argued in Politico that the then candidate had three clear beliefs: he was against trade, against alliances, and in favor of strongmen abroad.

Trump has stayed true to those beliefs during his first year in the White House. Soon after entering office, he withdrew the United States from the Trans-Pacific Partnership (TPP) and he has made clear his disdain for trade pacts such as the North American Free Trade Agreement. After railing against NATO on the campaign trail, Trump raised doubts about the United States’ commitment to Article 5—which provides for collective defense—when he declined to endorse it in a speech in Brussels (he finally reaffirmed the Article 5 commitment when back in Washington). And his admiration for authoritarian leaders has been evident, reflected in his public praise for the leaders of China, Russia, Saudi Arabia, and Turkey. These beliefs have proven quite sticky indeed.

Second, Trump has been hurt by his inexperience and lack of knowledge. His actions, including accidentally disclosing classified information to the Russian ambassador and trumpeting largely symbolic business deals with an increasingly assertive China—even as the other TPP countries try to move on with a multilateral deal without the United States—reveal a careless man with a naive belief in bilateral deals, not a master negotiator.

Third, Trump’s team has not been able to substitute for his lack of knowledge, even where it is experienced. Although Secretary of Defense James Mattis is running the Pentagon effectively, as a group, Trump’s advisers are neither constraining him nor channeling his preferences into coherent policies. For instance, as Susan Glasser reported for Politico, during his trip to Europe this summer, Trump removed a reference in his speech to NATO’s Article 5 at the last minute, blindsiding his team. The president’s constant Twitter threats against North Korea likewise undermine the notion of a coherent administration policy.

Trump and Japanese Prime Minister Shinzo Abe in Tokyo, November 2017. Reuters

TRUMP'S SURPRISES

Where Trump has really surprised is in the area of personnel. In one sense, his rejection of expertise should be expected, given the populist tenor of his campaign. But when one looks more broadly at the history of U.S. foreign policy, the sharp break between Trump and the Republican foreign policy and national security community is remarkable. This community was central to the “Never Trump” movement during the campaign, as symbolized by a March 2016 open letter opposing Trump that was signed by 122 Republican national security professionals. In return, Trump has refused to appoint these professionals to positions within his administration.

Instead, with a few notable exceptions, Trump has staffed his administration with remarkably inexperienced people. Most presidencies struggle to find their footing, and especially when their party has been out of power for a long time, new presidents often face the challenge of having knowledgeable appointees with little direct experience or years spent outside of government. But an inexperienced president deliberately choosing inexperienced advisers was, until Trump, essentially unthinkable.

The Trump administration has declined or failed to make appointments to an unprecedented degree, even leaving what most observers consider crucial foreign policy posts, such as ambassadorships in Europe and the Middle East, unfilled. Trump himself has left little doubt that this shortage, as well as the shrinking of the State Department, is deliberate, declaring in response to a question about State Department job vacancies that “I’m the only one that matters.”

Part of what makes Trump’s behavior in this area surprising is that although his rejection of expertise clearly has some political appeal, it also makes it harder for him to get the policies he wants. Even a president who wants to do less in the world still has priorities. Career officials can fill in on a temporary basis, but it takes confirmed political appointees to try to translate the president’s words into action.

The first year is typically when presidents make what I have called “policy investments,” which include staffing decisions, budgets, strategies and institutional creation and change. Presidents have varied in their skill at making these investments. But most, until Trump, have at least tried.

WHAT'S NEXT?

What should we expect for the remainder of Trump’s term? Not much learning, for one thing. Learning, when it takes place at all, is often slow. For instance, George W. Bush’s foreign policy evolved in his second term as he confronted the difficult realities of Iraq. But Bush read books and consulted with outside experts. Such learning requires openness to new ideas and new people, both qualities that Trump sorely lacks.

There are also likely long-term effects that we have not yet begun to appreciate. As Jim Goldgeier and I wrote in this magazine shortly after the inauguration, a lot of good foreign policy is invisible. Diplomacy, trade, and alliances—all things Trump disdains—have benefits that can be hard to see until they’re gone. But like an insurance policy, they are missed only when they are needed. Trump’s weakening of these foreign policy tools leaves the United States ill prepared for the crises that inevitably challenge presidents.

Trump’s leadership has confirmed a lot of what we know about how presidents shape foreign policy—but that is scary, given what we know about Trump. In the debate over whether Trump’s first year has been better or worse than expected, the real fear is that the worst is yet to come