Particularly important is the role of the Soviet Union—whatever you think of it in other respects, it clearly was critical in opening up space for a more humane order in Western Europe, which very few (at least in the US) are willing to acknowledge.

The only thing I would add is the role of the war and fascism in demoralizing and discrediting the old elites. Not only did they not stop it, but too many of them ended up on the wrong side, at least as collaborators.

This doesn’t apply exactly in the US, but obviously the partial leitimation of the Communists and the marginalizing of some major strands of traditional conservatism had everything to do with the war, and contributed to the gains of the welfare state here.

Other than that minor quibble, really excellent analysis.

it seems notable in this regard that countries that had never had a strong Marxist presence—England, the United States, Canada—also moved in this period toward the construction of much more elaborate welfare and regulatory states than had existed previously. In the American case, at least, this was done almost entirely by liberals shifting to the left without any real input from a vibrant socialist movement.

It’s largely forgotten now, but the Dutch economist and Nobel laureate Jan Tinbergen had a convergence theory which was once regarded as intellectually respectable. Convergence, mind you, not between more and less laissez-faire capitalist states, but between capitalist and communist economies. The western economies, so went the theory, were trending towards more management and even planning (under various names, one of them the so-called neo-classical synthesis, another one social democracy, a third one Keynesianism, a fourth one the New Deal and Great Society). The communist economies, if anyone remembers, were constantly struggling with how to overcome systemic rigidities, poor resource efficiency, poor quality and ever-present microeconomic imbalances. In the process they inevitably, and recurringly, employed various types of market-based mechanisms. Some of the most far-reaching were those of Hungary from 1968 onwards (New Economic Mechanism), but also Poland had them, as well as Yugoslavia (outside of the Soviet sphere of influence). The Soviet Union itself had several spates of reform attempts during the fifties and sixties with at least some market elements in them.

The theory had some plausibility as far as it went, but its empirical underpinnings were abruptly swept away by events from 1989 onwards, as convergence emphatically became a one-way street.