On Sunday evening, the BBC showed the first part of the landmark documentary on the Holocaust from 1985. Shoah was directed by Claude Lanzmann.

Everything you have ever heard about the overwhelming power of that remarkable and controversial film is true. If you were unaware of it, or if you haven’t seen it, I recommend that you try to find a way to get a copy.

Lanzmann took more than a decade to finish Shoah after recording hundreds of hours of testimony from witnesses, survivors and Nazis. He refused to use any archive images and delivered a very slow-moving film that is more than nine hours long. Upon release, it was not without its critics and the Polish government even protested to the French government on the grounds that it put too much emphasis on the complicity of Poles in the Holocaust. Poland’s leaders pointed out that many Poles had also perished in the camps.

But the controversy was a secondary issue. What matters most are the interviews with survivors bravely bearing witness to unimaginable horror. It is the 70th anniversary of the liberation of Auschwitz this month and a thought keeps coming back to me, astonishing me anew: To think that this was done here, in Europe, within living memory.

Halfway through I must admit couldn’t bear to watch all of Shoah again. It was too distressing. And such is the way of modern communication that when I tuned out to take a break, I turned to Twitter to learn that the far-left Syriza had done even better than expected in the Greek elections. As of last night, the party was projected to be just one seat short of an overall majority, meaning that a new Greek government will attempt to deliver “an end to austerity” by renegotiating the terms of the bailout which was given by other Eurozone countries in return for structural reforms.

This election result is a deeply troubling development, and not only because it could end with Greece leaving the Euro. Many British Eurosceptics would welcome the unwinding of a badly designed and misconceived project, the hope being that if Greece leaves it will encourage other countries to do the same, thus killing the Europhile integrationist dream.

I can see in theory how Grexit could – just could – work out that way. But the risk is high, surely, of it instead being a calamitous shambles that spreads panic to other countries, punctures multiple holes in vulnerable banks and hits growth.

This is the nightmarish dilemma created by the architects of the Euro and successive generations of leaders in southern European states who failed to get their populations to wake up to economic realities. Now, here come the leaders of the hard-left and populist right, tapping into public fury with the established parties.

But beyond the impact it might have on the immediate crisis in the Euro, it is the anti-market world view of some of those fast-rising alternative parties that is even more troubling. In particular, Syriza’s agenda is hard-left, high-spending, get-the-Germans-to-pay, big-government-has-the-answer craziness. Spain has its own surging far-left denouncing markets and promising to smash capitalism. In France the protectionist National Front is booming.

In Italy, the situation is different as mainstream Renzi, the rhetorical reformer, is popular and for now he has some leeway, as long as he gets on and delivers more than hot-air. Britain’s UKIP is in a different category again, of course. It is a peculiar blend, offering ostensibly Thatcherite prescriptions minus her enthusiasm for the EU’s Single Market. There are a small smattering of classical liberals in UKIP who like mass immigration but they can’t say so because the party’s voters hate it. UKIP’s views on the National Health Service are particularly confused.

What the new parties do all share is a creepy over-confidence that they are right, with exclusive access to the truth, and that big, simple, bold-sounding ideas are what are needed to sweep away all that hopeless compromise and complexity. This is unsettling to watch, especially when one considers where this kind of politics in the wrong hands has led ultimately in European history on other occasions. In the 1940s it led, with remarkable speed, to Treblinka, Sobibor and Auschwitz.

The situations – now and the 1930s – are not analogous, of course. I am not suggesting for a second that this latest crisis is about to lead to bitter street-fights between Left and Right, the emergence of dictators and a repeat of something like the Holocaust; only that once really crazy governments start getting elected amid economic chaos, it can lead anywhere.

In that context, today in Europe a hard-left party that despises markets and venerates Hugo Chavez has just won power. Its allies seek to do the same in some other European countries and leaders of mainstream left of centre parties may be tempted to offer more anti-market policies in an effort to combat the electoral threat. In such circumstances, those who believe in competition, economic freedom, robust institutions and limited government had better be ready to make the argument.