The United States has been behaving like a rogue state since the election of President Donald Trump.

The world is back in the early 1900s, when strongmen ruled and imperialism was the order of the day. Empire-building through might was the norm until World War II established a single power as the world industrial and economic hegemon with a military to match. That country was the US, with the Soviet Union and its Eastern European vassals as the main adversary.

US ascendancy

The US began its ascendancy to world hegemon after the 1898 Spanish-American War, when it began its own imperial expansion in the Western Hemisphere — and also took possessions such as the Philippines and Guam in the Pacific.

In World War I, the US came to the rescue or the United Kingdom and France — both imperial powers at the time — to push back the German Kaiser.

World War II ended with the destruction of Western Europe and much of the Asian Pacific — apart from countries such as Australia and New Zealand that were fortunate to avoid much of the aggression of Japan.

However, the key beneficiary of the war was the US. The US was untouched by World War II apart from the raid on Pearl Harbor in 1941 that dragged it into the conflict despite its reluctance.

Monroe Doctrine

Before all this, the US had been an isolationist power. In 1823, it adopted the Monroe Doctrine, which effectively stated it was supreme in the Western Hemisphere.

It was a reluctant interventionist in World War I. However, the entry of US troops in World War I gave the advantage to the UK and France over Germany and its allies. World War I was the beginning of the US’s march to world hegemon.

Then World War II firmly established its status. The US — through industrial power that supplied allies with the weapons that won the war — used industrial might derived from the battlefield to rebuild the war-devastated world. That project of rebuilding war-destroyed Europe and Asia established the US as the supreme economic and industrial power.

Currency

From 1945, the US dollar became the world reserve currency. The US — with the humble acquiescence of allies such as the UK and France, which in reality were little more than vassals of a triumphant US after the war ended — established the institutions that established a new world order at Bretton Woods in 1944: the International Monetary Fund, the United Nations, the World Trade Organization, the World Bank, and then the North Atlantic Treaty Organization.

For 80 years, the world order led by Bretton Woods organisations and the dollar, which was essentially liquid capital backed by American might, decided the standard and quality of life for most of humanity. The dollar was an especially powerful tool of hegemony managed by another supremely powerful US bank: the Federal Reserve.

Mr. Trump’s impunity and swagger at Davos last week was simply a raw display of this US power.