Ken Burns' history of the Vietnam war is getting many plaudits. What's not been noted about it, though, is that it reminds us of something we've forgotten - that the victory of capitalism over communism was not generally regarded as inevitable at the time. The idea that it was owes more to the hindsight bias than to historic fact. Indeed, capitalist triumphalism - of the sort we see from CapX, the IEA and Very Selective Reading of Wealth of Nations Institute - is relatively new.

What I mean is that the American government did not commit mass murder, sacrifice tens of thousands of its own young men, cause vicious domestic social divisions and jeopardise the economy in order to save Vietnam from a flawed economic experiment. It did so because it feared communism would succeed, not that it would fail - that communism could supplant capitalism. Equally, the Macarthyism of the early 50s was aimed not at rooting out cranks but genuine threats to American capitalism.

When Khrushchev spoke of "burying" and "overtaking" western capitalism, nobody laughed. The danger was a serious one. And the launch of Sputnik suggested to the world that Communism could produce technologies that eclipsed capitalist ones. As Francis Spufford showed in Red Plenty (discussed here and here) the Soviets had a genuine optimism that they could beat capitalism - and cold warriors feared they were right.

Yes Friedrich Hayek did warn that central planning was unsustainable. But he was regarded as a crank and outsider for most of the 50s and 60s. His was not the mainstream view.

In fact, fears for the viability of capitalism pre-dated the cold war. The classical economists all thought that capitalist growth would eventually cease. In 1848 - after decades of expansion - John Stuart Mill wrote:

The increase of wealth is not boundless: that at the end of what they term the progressive state lies the stationary state, that all progress in wealth is but a postponement of this, and that each step in advance is an approach to it.

(Marx's view that a declining rate of profit would eventually cause the collapse of capitalism was, in essence, just a riff on Ricardo's theory of diminishing returns.)

Yes, the classicals mostly approved of free markets. But they didn't think growth was inevitable. They were free market pessimists. In this tradition, Joseph Schumpeter wrote in 1943:

Can capitalism survive? No. I do not think it can...[Capitalism's} very success undermines the social institutions which protect it, and "inevitably" creates conditions in which it will not be able to live and which strongly point to socialism as the heir apparent...Prognosis does not imply anything about the desirability of the course of events that one predicts. If a doctor predicts that his patient will die presently, this does not mean that he desires it. One may hate socialism or at least look upon it with cool criticism, and yet foresee its advent. Many conservatives did and do. (Capitalism, Socialism and Democracy (pdf), p61-62)

On top of this, there was throughout the 19^th and 20^th centuries the constant fear of revolution. Bismarck's creation of the welfare state in the 1880s was an attempt to buy off working class unrest: that retreat from pure free market capitalism would of course be followed across the west over the next few decades.

And of course, anybody in the 1930s, seeing that capitalism had produced catastrophic war, hyperinflation and then depression, could not have been at all assured of its desirability or viability.

Capitalism, then, like bull markets, has climbed a wall of worry. Confidence that it is the best way of achieving sustained increases in living standards is quite a new phenomenon. It dates from the 1980s. And given that productivity and real wages have stagnated in the last decade, justifiable belief in such a proposition was tenable for only around 20 years.

Why, then, is it so widespread? I'd offer two suggestions.

One is that our ideas are disproportionately influenced by our formative years. Many people in their 40s to 60s were deeply impressed by the collapse of social democracy in the 70s and of communism in the 80s, but are less influenced by the capitalist stagnation of the last decade.

The second is that the alternatives to actually-existing capitalism have for years lacked salience: I'm not sure how far Labour's mild social democracy counts as a genuine threat to it. Yes, there are alternatives along the lines of participatory economics or market socialism for example. But these are sadly neglected. It's easy to be a capitalist triumphalist if you think the only alternative is Soviet-style central planning, just as you can believe yourself fit if you compare yourself to a fat slob.

Yes, capitalism has seen off one rival. Whether it can see off all - and whether it deserves to - is an open question.