He favours joining forces with Moscow, repudiating trade deals and pulling back from Nato. He sees climate change as "not one of our big problems", has not objected to Russia's annexation of Crimea and believes Saudi Arabia and South Korea should develop nuclear weapons if they feel threatened.
In the Middle East, meanwhile, he wants to reverse decades of US policy by moving the US embassy from Tel Aviv to Jerusalem. He has also called for torturing terrorists and "bombing the shit" out of areas under the control of Islamic State, which would constitute a war crime.
In other words, if president-elect Donald Trump acts on the foreign policy ideas he has expressed in the course of his election campaign, the postwar global order is about to be upended. Little wonder that the reaction of US allies across the world to Trump's shock victory ranges from nervousness to outright alarm.
The property developer’s election platform was built around a domestic agenda that promised to lift millions out of unemployment, revive economic growth and breathe new life into the decaying post-industrial heartlands.
His foreign policy pronouncements were confined to a single setpiece speech on the US's place in the world and vague slogans repeated in debates and interviews. If those thoughts were to be taken at face value, says Aaron David Miller, a vice-president at the Wilson Center, a Washington think tank, they would suggest the president-elect is "a muscular American nationalist with neo-isolationist tendencies".
The Trump doctrine, in that case, would reorient US policy in fundamental ways, retreating from foreign commitments and the promotion of liberal-democratic values overseas in favour of a transactional system of alliances founded only on strategic self-interest. As Miller puts it: “If Ally X is not contributing its fair share, I want to renegotiate the contract.”
If that were to happen and the US were to withdraw from the international order it has led for the last 70 years, it would be "the biggest shock to international stability since the second World War, and it will play out in very dramatic fashion", says Thomas Wright, a foreign affairs expert at the Brookings Institution in Washington.
Every president is a blind date, writer Jonathan Alter has said. With Trump, who despite the scrutiny of a long campaign largely remains a policy enigma, that is truer than ever. He is not the first president to lack foreign policy experience, but his predecessors all ascribed to a set of principles that had largely held firm for decades.
Trump, in contrast, has questioned policy pillars ranging from nuclear non-proliferation and the transatlantic alliance to the long-standing pledge to defend South Korea in case of attack from North Korea.
He has consistently praised Russian president Vladimir Putin and, to the alarm of many European allies, has signalled an openness to closer ties with Moscow at a time when relations between Russia and the West, poisoned by the war in Ukraine and the sanctions that followed, are at a low point.
The big question, however, is how many of these ideas Trump really believes or intends to see through.
“Will these proclivities and bumper-sticker slogans that Mr Trump has been using be forced to reconcile with the realities of what it takes to secure and advance the national interest of the United States?” asks Miller.
US administrations often act in reaction to their predecessors. Many observers saw Barack Obama's risk-aversion as a response to George W Bush's risk-readiness. Will Trump represent an even more violent departure? Or will he temper and modify his views when confronted with the realities of office?
Given Trump’s inexperience, a great deal could hinge on his choices to fill key positions at the state department, the Pentagon and the CIA. The businessman’s victory has created a dilemma for the Republican national security establishment, much of which distanced itself from the candidate.
About 150 of the Republican party's most prominent national security specialists signed open letters in March and August in outright opposition to Trump's candidacy. One said he was "utterly" unqualified for the White House. The other warned that he would be "the most reckless president in American history".
Names circulating in recent days for the secretary of state role include close allies such as Newt Gingrich, a former speaker of the House of Representatives, and Senator Bob Corker, the chairman of the Senate foreign relations committee.
Also on the shortlist may be John Bolton, a controversial US ambassador to the United Nations under former president George W Bush. Among those reportedly in the frame for secretary of defence are Senator Jeff Sessions, who has advised Trump on policy, and Gen Michael Flynn, a former director of the Defense Intelligence Agency.
On Russia, for example, opinions differ quite significantly within that group. "So far Corker has been very tough on Russia. He has been leading in the Senate the move for the US to supply the Ukrainian army with lethal defensive weapons," says Angela Stent, director of the Center for Eurasian, Russian and Eastern European Studies at Georgetown University.
“But Gen Flynn has been advising Trump and has nice things to say about Russia. If he gets a high-level position, I think that would indicate a more open position towards Russia.”
And yet there are limits to the influence of any president’s entourage. Miller, a Middle East specialist who worked for six Republican and Democratic secretaries of state, says advisers often produce conflicting recommendations.
“I don’t know how the management style of running a real estate company is going to track with the realities of having to make decisions on complex issues when your advisers disagree,” he says.
“It’s one thing if you get a consensus recommendation on an issue. It’s another when your advisers are split. You then bear the major responsibility for adjudicating the differences and making the decision.”
Taking encouragement from a candidate’s incoherence is hardly a position US allies want to be in, but those who hope Trump will reverse or tone down some of his more controversial positions can find a glimmer of reassurance in his campaign, where he showed a willingness to row back when necessary.
On immigration, his early proposal to build a wall, force Mexico to pay for it and deport 11 million undocumented migrants morphed into a plan to get Mexico to pay not for a wall but for deportations targeting "gang members" and "drug peddlers". He also did not rule out a type of immigration reform plan involving a pathway to citizenship for the undocumented.
Similarly, a proposal for “a total and complete shutdown of Muslims entering the United States” became a vague plan for “extreme vetting”. On the fight against Islamic State, Trump pulled back somewhat in the latter stages of the campaign, insisting he would not order the military to do anything illegal.
In the same vein, the office of South Korean president Park Geun-hye announced that, in a telephone conversation with Ms Park on Wednesday, Trump pledged his commitment to defending South Korea under the existing security alliance – a position he had put in doubt during the campaign.
“He said lots of very provocative things in his campaign. Let’s see how much he actually tries to implement,” says Stent.
Miller agrees. Recent days have shown that the electoral laws of gravity have been suspended, he says. “The question is whether those political laws of gravity will be suspended when it comes to the only issue that counts, which is governing.”