On August 16th, Donald Trump announced a substantial reduction in joint military exercises with South Korea. On August 19th, he announced what came, five days later, to be called “Operation Economic Outcast” against Iran, defined as an effort to “sever the economic lifelines that sustain the Iranian regime”. On August 21st, US trade talks with Canada collapsed, after the Americans made new demands that would limit Canada’s freedom to make trade deals with other countries and keep its rules protecting the French language. On August 28th, Trump announced “THE BIGGEST OIL DEAL IN WORLD HISTORY!” which would give the US 55 per cent control of the output of a new Venezuelan company that would develop 17 fields with a “proven potential” of 65 billion barrels.That is an astonishing effort in just two weeks. The behaviour itself is not surprising. But it does reveal the sort of world Trump believes in. It is a world in which the US does not have allies but satellites; one in which the US can do whatever it wants, whenever it wants, to whomever it wants; one in which power alone matters; and, above all, one in which the US thinks that it alone has the power, with that power concentrated in the hands of one man, who is, not coincidentally, a bully.It was not ever thus. In 1969, Dean Acheson, secretary of state to Harry S Truman from 1949 to 1953, published Present at the Creation: My Years in the State Department, in which he laid out the logic of post-second world war US policy. In its prologue, he describes “a tale of large conceptions, great achievements, and some failures ... Its hero is the American people, led by two men of rare quality, President Truman and General Marshall.” He goes on to explain “the enormity of the task before all of them” as being “to create half a world, a free half” out of chaos, “without blowing the whole world to pieces in the process. The wonder of it is how much was done.” Yes, it truly was.Because of what they then created, the then embattled “free half” won the cold war, the last of the great European empires, the Soviet Union, fell and much of the world dreamt of peace and prosperity. When Trump writes his autobiography, I hope he calls it Present at the Destruction. That is not because he was personally responsible for the death of those dreams. But he is certainly the man now nailing their coffins shut.Just consider the four actions he took in the two weeks briefly noted above. We are in a lawless and unpredictable world. Trump is not the creator of that world. But he is surely its prime mover. Let us start with the story of South and North Korea. The Korean War began when the latter invaded the former in 1950. Overall casualties of this conflict were some 5 million. The US itself lost 37,000 soldiers in the three years of conflict. Today’s long-lasting armistice, not a true peace, was the result.When explaining his decision to cut down this year’s exercises, Trump cites his “very good relationship with Kim Jong-un”, hereditary ruler of a communist regime. Moreover, it is not just any communist regime: North Korea is the world’s most totalitarian country. South Korea, however, is the product of one of the world’s greatest economic miracles and a democracy now rated more highly by Freedom House than the US. The exercises never caused a war. But cutting South Korea off might.US president Donald signing an executive order to change the name of Lake Ontario to "Lake America" in the Oval Office last week. Photograph: Demetrius Freeman/The New York Times