There was a warning of what was to come during the election campaign with Joe the Plumber, to whom Mr Obama unwisely confided his intention to "spread the wealth around". Americans who have risen from poverty to become qualified tradesmen or entrepreneurs generally believe that they have a right to put what wealth they produce back into their own businesses, rather than trusting governments to spread it around among those judged to be deserving.

But Joe's warning was not heeded. Most of the constituency whose instincts were the same as his voted for Obama, and have now lived to regret it. This in itself is not especially surprising: it could simply be seen as the self-interested politics of personal survival. What is more startling is the growth in America of precisely the sort of political alignment which we have known for many years in Britain: an electoral alliance of the educated, self-consciously (or self-deceivingly, depending on your point of view) "enlightened" class with the poor and deprived.

America, in other words, has discovered bourgeois guilt. A country without a hereditary nobility has embraced noblesse oblige. Now, there is nothing inherently strange or perverse about people who lead successful, secure lives feeling a sense of responsibility toward those who are disadvantaged. What is peculiar in American terms is that this sentiment is taking on precisely the pseudo-aristocratic tone of disdain for the aspiring, struggling middle class that is such a familiar part of the British scene.

Liberal politics is now – over there as much as here – a form of social snobbery. To express concern about mass immigration, or reservations about the Obama healthcare plan, is unacceptable in bien-pensant circles because this is simply not the way educated people are supposed to think. It follows that those who do think (and talk) this way are small-minded bigots, rednecks, oiks, or whatever your local code word is for "not the right sort".

The petit bourgeois virtues of thrift, ambition and self-reliance – which are essential for anyone attempting to escape from poverty under his own steam – have long been derided in Britain as tokens of a downmarket upbringing. But not long ago in America they were considered, even among the highly educated, to be the quintessential national virtues, because even well-off professionals had probably had parents or grandparents who were once penniless immigrants. Nobody dismissed "ambition" as a form of gaucherie: the opposite of having ambition was being a bum, a good-for-nothing who would waste the opportunities that the new country offered for self-improvement.

But now the British Lefties who – like so many Jane Austen heroines looking down on those "in trade" – used to dismiss Margaret Thatcher as "a grocer's daughter", have their counterparts in the US, where virtually everybody's family started poor. Our "white van man" is their Tea Party activist, and the insult war is getting very vicious. It is becoming commonplace now for liberals in the US to label the Tea Party movement as racist, the most damaging insult of all in respectable American life.

So the Democrats, who once represented the interests of ferociously self-respecting blue-collar America, are now seen – under their highly educated president, who wholeheartedly embraces the orthodoxy of the liberal salon – as having abandoned their traditional following. Which is precisely what Labour did here when it turned its back on what used to be called "the respectable working class" because of its embarrassing resentments and "prejudices" against welfare claimants, immigrants, and anti-social youths. Bizarrely, among people who see themselves as profoundly empathetic, there was an utter failure to understand why the spirit of benevolent understanding and tolerance did not flourish among those whose daily lives were directly affected by a mass influx of foreign workers, or local delinquency, or a welfare system that rewarded inertia.

So who will speak – both here and over there – for the aspiring, the enterprising, the law-abiding, and, perhaps most important of all in these economic times, the productive classes? Mr Cameron seems unsure whether he wishes to recapture the Thatcher constituency of C1s and C2s, or to cultivate the liberal drawing rooms with a green/overseas aid/gay marriage portfolio. He speaks warmly of the virtuous and hard-working, but his tax policies will make them pay off most of the national deficit out of their own pockets.

In the US, there is probably no going back for the Obama administration. It has definitively lost faith with the "little guy" voters who once thought of a Democratic presidency as a form of divine protection, and this president does not seem to have the ingenious flexibility of a Bill Clinton, who swung Right after his first disastrous years in office, partly under pressure from a Republican Congress.

What is most depressing about this – apart from the injustice of it – is that the people who have been disenfranchised and disowned are the very ones on whom both countries' economic recovery depends.