ON September 11, 1973, the Chilean Air Force bombed the presidential palace in Santiago. That afternoon, President Salvador Allende shot himself rather than surrender to the army. For the next 17 years, under the dictatorship of General Augusto Pinochet, democracy was suspended.

Scottish trade unionists simply refused to engage with the Pinochet regime. They opposed its atrocities and stood in solidarity with the workers of Chile. When the engines of air force planes were shipped to East Kilbride, Rolls Royce workers refused to handle them. It was a noble act of defiance.

In 1976, when Milton Friedman went to Stockholm to collect his Nobel Prize, there were protests. Friedman, and several other members of Chicago University’s economics department, had visited Chile since the coup. A group of former students, the Chicago Boys, were giving the new regime advice about how to liberalise the economy.

Fundamental to Friedman’s political philosophy was the belief that economic freedom – and the absence of government from the detail of peoples’ lives – will bring large benefits to people, both individually and collectively.

In 1980, in Free To Choose, one of the books he wrote with his wife, Rose, they began by claiming that “Adam Smith’s key insight was that both parties to an exchange can benefit, and that, so long as cooperation is strictly voluntary, no exchange will take place unless both parties do benefit.”

This principle of voluntary exchange is so fundamental in economics that most students probably meet it in the first two weeks of their studies, and then probably forget all about it. For the Friedmans, though, it was not just part of the furniture, present in the background but easy to ignore.

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It was critical for their arguments about why we should prefer the economy to be self-organising, rather than centrally planned. They wanted people to choose their idea of freedom, rather than what Friedrich Hayek, in his earlier polemic, had called The Road to Serfdom.

There is an important political context here. Free To Choose was an economic handbook, written on the back of a TV series, just before Ronald Reagan’s triumphant presidential election victory in 1980. It was not part of the campaign, but it added to the conservative mood music in the USA.

Set aside the political stance for a moment. The Friedmans were excellent at setting out complex ideas simply and directly, and persuading people that some of their more radical ideas should be implemented. A Friedman presentation always seemed entirely reasonable while it was going on. The arguments were always coherent.

In many ways, they repackaged Hayek’s argument that liberty is the absence of coercion. For Hayek, the state has a duty both to ensure that it has a monopoly of coercive power, and to allow citizens to challenge its exercise of that power because it will only be applied according to law. The liberal state is legitimate only because it agrees to restrain its use of power.

The Friedmans did not simply oppose socialism, They abhorred all forms of economic planning.

If you hear an extreme Republican speaking today, they will ignore the distinction, and call everyone else a socialist. All planners are socialists. In this binary classification, any small step away from perfect liberty will begin the descent into the darkness of a totalitarian state.

A coup d’etat, with a repressive dictatorship replacing a democratically elected socialist government, was tolerable because it promised the recovery of that liberty.

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At much the same time as Friedman was active, the SNP lost most of their seats in Westminster in the 1979 election. Mrs Thatcher moved into 10 Downing Street, with Friedman and Hayek providing the ideas.

Young SNP activists, eager to slough off the lazy accusation that the party was filled with tartan Tories, formed the 79 Group. Much of the intellectual ballast for its critique of the SNP’s policy came from the economist Gavin Kennedy, later a Smith scholar.

The 79 Group members were expelled from the SNP, rejoined, and provided it with leadership, direction and renewed purpose. That helped it to take on the Labour Party.

Throughout this year, the 300th anniversary of his birth, academics will have many discussions about Smith. European scholars have never accepted the view of right-wing American economists that he was a libertarian. Philosophically inclined, and historically aware economists, like Gavin Kennedy and Deirdre McCloskey, ranking his Theory Of Moral Sentiments above The Wealth Of Nations, know that Smith had a far more complex political philosophy.

He was, though, undoubtedly a liberal. His understanding that a self-organising, decentralised economy would often function well is an important part of his intellectual legacy. But he also knew that there were many circumstances in which public action, and social institutions, would be better than markets.

The SNP, competent as the Scottish Government, frustrated in their attempts to find a way of bringing the constitutional question to a head, have now pitched their big tent a little left of the centre of Scottish politics.

To its right, there are only Unionist parties. I do not understand why that should be.

Perhaps out of this year’s reflections on Smith’s legacy, some bright young people will start making the case for a liberal Scotland: integrated into Europe, a leader on climate change, committed to providing excellent health care and education, and committed to individual liberty, so that the independence family is complete.