Every American president since Harry Truman has arrived in the White House committed to globalism — a belief that America must lead always and everywhere — as the central organising principle of US foreign policy. In recent years, we have seen Barack Obama’s faith in globalism waver. The prospect of President Donald Trump abandoning globalism altogether is real.

For US allies as varied as Britain, Japan, Saudi Arabia and Israel, American globalism has been the gift that has never stopped giving. Nations enjoying a ‘special relationship’ with Washington have relied on American power to shield them from danger and, to some extent, from bearing the consequences of their own folly, past and present.

Listen to Andrew J. Bacevich and Freddy Gray discussing Trump’s foreign policy

Motives other than kindness and goodwill have shaped US policy throughout. Sustaining American globalism has been the conviction that its benefits are reciprocal and its costs affordable. British diplomatic and military support has on multiple occasions endowed American muscle–flexing with a sheen of legitimacy, especially since the end of the Cold War. Japan’s willingness to host US forces has helped sustain American primacy in the Pacific, won at Japanese expense in 1945. In return for guaranteeing the security and survival of the Saudi monarchy, the US gained privileged access to the world’s most abundant oil reserves. Providing extraordinary military largesse and diplomatic cover to Israel ostensibly kept alive prospects of resolving the Israeli–Palestinian conflict, believed in some quarters to hold the key to restabilising the Middle East.

At the outset of his presidency, Obama was a true believer in American globalism. Yet his was a faith that had not been tested. Over the course of his two terms, a succession of crises and disappointments transformed believer into sceptic. It’s not simply that in places like Iraq and Afghanistan, displays of American leadership did little except exhaust America’s military and drain its treasury. Equally (perhaps even more) important was the growing evidence that US allies were not holding up their end of the bargain. In the so-called ‘war on terror’, the Saudis were manifestly playing a double game. For its part, the government of Benjamin Netanyahu was maliciously creating obstacles to the two-state solution in which a succession of American administrations had invested so much attention. And as for the second world war allies and adversaries who had turned to Washington for assistance in recovering from that catastrophe, here they were, decades later, still sticking the Americans with the tab for Nato, ostensibly a security partnership. Even more than his predecessors, Obama had little patience with ‘free riders’.

Enter Donald Trump, the designated heir of the Obama legacy.

It is always difficult to predict what an incoming administration will do — who could have imagined George W. Bush embarking upon a crusade to democratise the Islamic world? Trump’s background and personality make forecasting more uncertain still.

That Americans have handed the keys to the White House to a foreign-policy novice is not particularly novel. The last time my countrymen elected a president possessing any measurable prior knowledge of how the world worked was in 1988 — George H.W. Bush. Since then, we have treated the post as a chance for on-the-job training, with mastery to be gained through trial and error.

The things that set Trump apart from his immediate predecessors are his lack of fixed convictions and his erratic temperament. Given the narcissism that may well be his dominant trait, his own impulses and inclinations will supersede what others have put in place. He is unconstrained by precedent. There is no playbook to which he will conform, no past practice he will feel obliged to honour. Trump’s confidence in his ability to grasp the essentials of any situation and to intuit a solution is seemingly without limits. Acquired expertise — the coin of the realm among diplomats, intelligence professionals and senior military officers — counts as nothing. Trump knows more than they possibly can. Oblivious to the contradictions inherent in what he says from one day to the next, inclined to snap back at any perceived slight, Trump gives every indication of being a uniquely unpredictable president.

Not that earlier occupants of the White House have always been models of constancy. In 1914, Woodrow Wilson adamantly opposed US entry into the first world war and persisted in that view until insisting just as adamantly that it had become a strategic and moral imperative. Before 1939, Franklin Roosevelt was anything but an internationalist; as the Wehrmacht overran Europe, his outlook changed. Notably, however, once having revised their stances, Wilson and FDR stood firm. Having turned, they did not turn back. And with good reason: unpredictable behaviour on the part of any great power, leaving allies and adversaries alike wondering what will come next, is a dangerous trait — something that Donald Trump gives little sign of appreciating. Unpredictability is a Trump signature.

All of this explains why the foreign–policy establishment views Trump’s ascent to the Oval Office with trepidation. After all, as a candidate, Trump presented himself as the enemy of the establishment, a property tycoon promising salvation to working-class Americans. He vowed as president to ‘drain the swamp’. For Trump’s supporters, the swamp is Washington DC and all that it represents: an arrogant, corrupt, self–aggrandising elite that feathers its nest at the expense of ordinary people.

Out of whatever combination of patriotism or self-interest, denizens of that swamp have therefore paid acute attention to how the president-elect has gone about assembling his national security team. Here would be the first indication that the establishment’s days might be numbered. Beyond that, if Trump were to be tamed or tempered or at least kept from going off a cliff, the challenge of doing so would fall to those in a position to counsel him on matters of basic policy. Far more than is usually the case, the composition of the group invited into the White House Situation Room to advise this particular president in the midst of some unfolding crisis seems likely to matter.

Although that team is not fully chosen, it is already evident that concerns about Trump turning US policy over to rubes and yokels from outside the Beltway were misplaced. Trump’s senior appointees are all fully credentialled, card-carrying members of the establishment.

Trump has picked the chief executive of a multinational corporation that has global interests as his secretary of state. To run the Pentagon, he has chosen a retired four-star general. A retired three-star general will fill the post of national security adviser, with another as that official’s ‘chief of staff’. Yet another retired four-star general will head the Department of Homeland Security, the agency that actually defends the United States while the Defence Department tries to police the planet. None of these individuals even remotely qualifies as an anti–establishment figure.

Yet it’s fair to note that the American foreign establishment is not homogenous. If broadly committed to perpetuating globalism, its members differ on how to do so. Trump has drawn his appointments from a particular wing of the establishment, one that tends to be doctrinaire, confrontational and fixated with short-term outcomes. Let’s call it the John Foster Dulles/Dean Rusk wing of the establishment, in contrast with the Dean Acheson/George Kennan wing, which shows greater subtlety and flexibility, while playing a longer game.

In the history of American statecraft, these are top-flight names. As secretary of state under President Eisenhower, Dulles embraced ‘brinksmanship’ — diplomacy as a game of chicken. Serving in that same position for eight years in the 1960s, Rusk supported US intervention in Vietnam and left office still insisting that the war was entirely justified. Acheson, whose long public career culminated in a term running the State Department for Harry Truman, was hardly a dove. He and Kennan, the department’s leading Soviet expert at the time, devised the strategy of containment, which guided US policy throughout the Cold War.

Neither wing of this establishment is impervious to error. Neither has a lock on wisdom. But the Dulles/Rusk approach yielded a horrendous nuclear arms race, misguided coups and an epic debacle in Southeast Asia, whereas the Acheson/Kennan approach is chiefly remembered for the Marshall Plan and the creation of Nato. One can sense an affinity between the Dulles/Rusk MO and Trump’s own pugnacious inclinations, his promise to ‘bomb the shit’ out of Isis being a vivid example.

Which of Trump’s advisers will win his confidence and emerge as authoritative interpreter of last night’s presidential tweet — or whether Trump will prefer any advice to his own instincts — is yet to be determined. With that in mind, the forthcoming Senate confirmation hearings for the secretaries of state, defence and homeland security will command considerable attention. These will provide some sense of what each appointee thinks, whether their views align, and how their own opinions compare with those that Trump himself compulsively announces via Twitter.

Regrettably, the position of national security adviser does not require Senate confirmation. So Lieutenant General Michael Flynn, the Islamophobic ideologue who is Trump’s choice for that post, will receive no public vetting. Notably, as Trump began rolling out his team, Flynn was among the first appointments announced, perhaps portending that at least initially he will be primus inter pares — a troubling prospect.

As if to flaunt his contempt for orthodoxy, candidate Trump resurrected the loaded phrase ‘America First’, an artefact from an era when large numbers of Americans saw globalism — or more immediately, coming to the aid of a beleaguered Britain — as a one-way trip down the road to perdition. In the present era, characterised by long, seemingly unwinnable wars, the sentiment implied by that old slogan finds fresh appeal. Americans are an impatient people. They don’t like long wars any more than they like long lines, whether at supermarkets or airports. And they don’t like the sense of being played for suckers.

During the campaign, Trump exploited these sensitivities with considerable skill. Yet whether ‘America First’ represents expedient posturing or future intent remains to be seen. One may doubt whether even Trump knows for sure.

If there is one thing Trump does know, it’s a balance sheet. Profit and loss: these define success and failure, results that are acceptable and ones that are not. When it comes to foreign policy, that balance sheet is today badly out of whack — so at least many Americans have come to believe. Endorsing that view helped make Trump president.

It now falls to Trump to correct the imbalance, something he claims with his trademark swagger that he will do in short order. Should he succeed — should the United States ‘win so much people will say we can’t take it any more’ — some modified version of American globalism may persist. Should he, along with the generals and billionaires comprising his inner circle, come up short, then the tentative retreat from globalism that began under Barack Obama will continue and even accelerate, with large implications for the United States and the world as a whole.