In 1927, the American Communist leader Jay Lovestone aroused Moscow’s ire by arguing that industry in the United States was so youthful and vigorous as to be exempt from the traditional Marxist laws of capitalist crisis and decay. ‘American exceptionalism’ – the phrase that the Soviet leader Joseph Stalin used to describe Lovestone’s heresy – then went underground for more than half a century, only to emerge in the 1980s, strangely enough among US neoconservatives.

Standing Stalin on his head – or, as they would undoubtedly prefer, on his feet – the neocons argued that the US was exceptional after all, not just ‘the indispensable nation’, as the Secretary of State Madeleine Albright would later have it, but fundamentally different from every other country on Earth. Newt Gingrich wrote an entire book celebrating American exceptionalism while the Republican presidential candidate Mitt Romney repeatedly invoked it on the 2012 campaign trail. ‘Our President doesn’t have the same feelings about American exceptionalism that we do,’ he complained. Not to be outdone, Barack Obama declared in a major foreign policy address last year: ‘I believe in American exceptionalism with every fibre of my being.’

As much as one might be tempted to write this off as typical American bluster, it happens to be correct – although not in ways the politicians realise. The US is exceptional. It’s exceptionally big, with two and a half times the population of any other member of the Organisation for Economic Cooperation and Development (OECD), an organisation that includes most of the world’s richest countries. The US is also exceptionally wealthy, with a per-capita income at least 40 per cent above the OECD average. And it’s exceptionally powerful, with more than 700 military installations across the globe and a military budget greater than that of the next eight nations combined.

The US is exceptional in another way, too: constitutionally. Other countries have their parliaments and heads of state. But no other country invests such authority in a single document dating from the era of silk knee britches and powdered wigs. Sealed in moisture-controlled, bullet-proof glass containers that are on display in a special rotunda at the National Archives Museum in Washington DC by day and lowered into a multi-ton bomb-proof vault by night, the Constitution is to the US what the Bible was to medieval Europe or the Qur’an to today’s Islamic State, albeit with certain differences.

It’s much shorter: just 4,000 words in its original 1787 version. It’s also more rigorous and to the point: you don’t have to parse a story about Abraham or Moses to learn how the Congressional spending process works. All you have to do is turn to Article I, section 7, and learn that ‘all bills for raising revenue shall originate in the House of Representatives; but the Senate may propose or concur with amendments as on other bills’ – which is more or less how things still work today....