For those who hope that Donald Trump has no views on foreign policy, forget it. Not only does he have a view about America’s role in the world, but it is one shared by many Americans. He may or may not cosy up to Vladimir Putin, have a trade war with China or even build his wall. But on the biggest question of all, from which everything else flows, the question of US responsibility for global order, he clearly has little interest in continuing to shoulder that burden. He aims to put America First, which means we are closer to the end of the 70-year-old US world order

Mr Trump, in this respect, is no anomaly. Pat Buchanan rode “America First” a long way against George HW Bush of New World Order fame in 1992; and after the Iraq and Afghan wars and the financial crisis, it became a national phenomenon. Internationalists such as Jeb Bush and Marco Rubio went nowhere this year; Bernie Sanders joined Mr Trump in attacking global involvement; and Hillary Clinton was hit from all sides for being too internationalist and too wedded to the idea of the US as the “indispensable nation”, the Bill Clinton phrase that encapsulated the thinking of every president from Harry Truman to George W Bush. President Barack Obama was the transitional figure away from that tradition, and Mr Trump’s election is the decisive break. The US is, for now, out of the world order business.

This does not mean a “return” to a mythical American isolationism. This powerful, commercially minded nation has never cut itself off from the rest of the world, not even in the 1930s. What it does mean is a return to national solipsism, with a much narrower definition of American interests and a reluctance to act in the world except to protect those narrow interests. To put it another way, America may once again start behaving like a normal nation.

A hypercritical Europe, with its own solipsism, has often taken for granted just how abnormally unselfish American behaviour has been since the second world war. No people ever took on such far-flung responsibilities for so little obvious pay-off. The US kept troops in Europe and Asia for 70 years, not to protect itself from immediate attack but to protect its allies. With half the world’s gross domestic product in 1945, it created an open economic order that let others prosper and compete. It helped spread democracy even though democratic allies proved more independent than the dictatorships they replaced.

All this was profoundly in US interests, but only when viewed from a most enlightened perspective. Americans came to that enlightenment only after a world war, followed by the rise of Soviet communism, which persuaded them to define their interests broadly and accept responsibility for a liberal world order that benefited others as much as, sometimes more than, it benefited them.

Enlightenment doesn’t last for ever, however, and with Mr Trump’s election Americans have chosen, as in 1920, a return to normalcy. So what does the normal solipsistic superpower do? It looks for immediate threats to the homeland and finds only one: radical Islamist terrorism. Its foreign policy becomes primarily a counterterrorism strategy. Nations are judged not by whether they are allies or nominal adversaries, democracies or autocracies, only by their willingness to fight Islamists. Mr Putin’s Russia, Abdel Fattah al-Sisi’s Egypt, Bashar al-Assad’s Syria, Israel: all are equal partners in the fight and all are rewarded with control, spheres of influence and defence against critics within and without. Most countries, by this calculus, are irrelevant.

The rest is a matter of money. Foreign policy should serve US economic interests, and where it doesn’t should be changed. Trade deals should be about making money, not strengthening the global order or providing reassurance to allies living in the shadows of great powers. The US is no longer in the reassurance business. For decades an abnormal US foreign policy has aimed at denying Russia and China spheres of interest. That made sense when upholding an order to avoid a breakdown like that of the first half of the 20th century. But a narrower reading of US interests does not require it. What interest is it of the US who exercises hegemony in east Asia and in eastern and central Europe? Existing alliances need not be re­nounced — that would be messy — but, if allies have to adjust to new realities, that is to be welcomed rather than resisted.

As for the projection of US military power abroad, there should be no need. No foreign army threatens the homeland. Nuclear powers can be deterred by America’s nuclear arsenal. (Note to US hawks: there will be no bombing of Iran under a Trump administration.) Almost every intervention of the past 70 years was primarily to defend someone else or to uphold some principle of global order. They were “wars of choice”, not required by a narrow definition of US interests. The war against radical Islamist terror can be fought by drone strikes a few special forces and by our partners on the ground.

None of this should sound far-fetched. This narrow, interest-based approach to foreign policy was dominant in the 1920s and 1930s. It is the preferred strategy of many American academics today. More importantly, it plays well with an American public that has come to believe the US has been taken to the cleaners. Mr Trump promises they will not be taken for suckers any more.

How long can this new era last? Who knows? Americans after 1920 managed to avoid global responsibility for two decades. As the world collapsed around them, they told themselves it was not their problem. Americans will probably do the same today. And for a while they will be right. Because of their wealth, power and geography they will be the last to suffer the consequences of their own failures. Eventually they will discover, again, that there is no escape. The question is how much damage is done in the meantime and whether, unlike in the past, it will be too late to recover.

The writer is a senior fellow at the Brookings Institution and author of ‘The World America Made’

Robert Kagan is a Senior Associate at the Carnegie Endowment for International Peace and the author of The Return of History and the End of Dreams.