Here follow pairs of facts about the contemporary US. The economy added 850,000 jobs in one month; a third of voters believe the last presidential election was stolen. A lockdown with no peacetime precedent cost just 3.5 per cent of national output; states as large as Georgia are curbing the independence of election officials. At 7 per cent, anticipated economic growth this year is that of mid-2000s China; a twice-impeached president is near-favourite to clinch the next Republican nomination.

America’s economic and civic prospects could hardly be more divergent. The war against cliché stops me reciting the first sentence of A Tale of Two Cities. But Americans really can claim to have “everything before us” and “nothing before us”, to be savouring spring and enduring winter all at once. Their nation has arrived at a sort of affluent dysfunction.

For a certain kind of materialist, sure that economics drives everything from individual criminality to national politics, this is jarring stuff. It was bad enough that China’s enrichment did not make it a vast Netherlands of multi-party pluralism. How much worse that even the US defies what link there ever was between economic and political progress. After an era in which it out-innovated western Europe and Japan, it could not pull off a bloodless transfer of power.

The US is now between a quarter and a third richer than Britain. Which country’s 2024 election gives you the queasier feeling? The US has higher income per head than even Germany. Which democracy would you bet on to be functional by mid-century?

Beyond a certain point, it seems, the civic returns on economic growth are nil or even negative. The left’s theory is that distribution counts for more than raw scale of wealth or its rate of growth. Too wide a gap between rich and poor tests the tensile strength of their civic bond. There is a darker explanation to entertain, though: that something about prosperity itself frees voters to toy with politics. Call it recreational extremism. In the coda to The End of History and the Last Man, perhaps the most cited book that no one finishes, Francis Fukuyama warned as much.

Whatever its cause, America’s economic and civic decoupling is easy to spin favourably. The story is not that a rich country is so politically broken but that a politically broken country is so rich. As such, American declinism misses the point. Weimar Germany and pre-Caesar Rome are among the frail republics to which the US has drawn comparison. In fact, its productive entropy suggests nothing more troubling than postwar France.

Between 1945 and 1975, France enjoyed years of material gain that are still hailed as the “Glorious Thirty”. Over this period, its political record includes: a near-miss presidential assassination, an Algerian war that was officially a civil war, the Suez crisis, semi-detachment from a US-led west, the dissolution of the Fourth Republic, almost monarchical rule under Charles de Gaulle and, to enliven a quiet May, the worst civil unrest in memory. The France of good living and grands projets was the France that partially banned The Sorrow and The Pity, a full generation after the Nazi-French collusion it documented.

The lesson here is consoling or chilling, according to taste. A nation can prosper despite its politics. Beyond an institutional minimum — tax-collecting bureaucracy, incorruptible courts — it is possible to get away with almost feral dysfunction. The US has a large minority of people who are unreachable in their reactionary paranoia. It also has a progressive fringe that views colour-blind liberalism as Oldthink.

All the way down to a paramilitary right and campus-trained, theory-spouting left, the portrait of America as mid-20th century France holds. No less deftly than that other republic, though, it seals off its grim public square from an economy that just does what it does. Viewed from this angle, California is not a world unto itself but the nation in miniature: a place where woeful politics and scarcely believable dynamism cohabit.

I don’t mention this resilience to praise it, at least not without qualms. On balance, it must be an invitation to later trouble. If flirting with cranks, demagogues and nihilists carried a material price, voters would flinch from it. As it is, there has been so little cost to these dalliances that only a churl would blame them. As long as extremism is free, at least economically, what is an errant citizen’s incentive to moderate? Just honour, perhaps, and the hunch that even a superpower can only ride its luck so far.