One consequence of the disappearance of Marxism from the political scene in the west is the widespread illusion that politics can be separated entirely from economics.

This is strikingly apparent in much of the analysis of things like the rise of Donald Trump and Brexit. Materialist analysis has been side-lined in favour of a focus on moral judgements, with commentators basking in the satisfying 'ecstasy of sanctimony' that comes with blanket condemnation. Debates are increasingly framed in terms of good, wholesome and open-minded folk verses incorrigible 'deplorables'. Meanwhile, political instability is blamed on an almost magical personal defect labelled 'intolerance'. The dialectical relationship between the economy and human ideas about the world has been effectively severed.

We see this too in the reaction to burgeoning protests in Iran, though typically this works the other way around. Even though politics can never be entirely separated from economics, we have heard it said repeatedly this week by news anchors that the protests gripping Iran are 'mainly economic'. The implication being (rather offensively if you are gay or a woman) that, beyond issues like wages, there is little in Iran – a Shiite theocracy - to be politically embittered about.

Yet as Kaveh Sharooz, a Toronto-based human rights activist, told my friend the Canadian journalist Terry Glavin this week, in Iran as elsewhere "you can't separate politics from economics". Sharooz served as prosecutor in the 'Iran Tribunal', an initiative to assemble a case against senior Khomeinist officials on charges of crimes against humanity during the 1980s. "Bad politics leads to bad economic decision-making," Sharooz told Glavin, "which leads to poverty and all the misery you're seeing in Iran".

This ought to be obvious when one considers that the IRGC – the hard-line Islamic Revolutionary Guard Corps – controls around 15 per cent of Iran's economy. While the Iranian dictatorship has been pumping millions of dollars into propping up its sectarian bedfellow in nearby Syria, some Iranians inevitably wonder why they live in squalor. This seems an especially pertinent question when, according to a UN-backed analysis from 2014, around half of Iran's urban population live below the poverty line.

The retreat of class analysis in the west is most obviously felt on the left. Of course, at this point most lofty declarations of 'solidarity' with those protesting in Iran are largely performative. There are few practical and material things that we in the west can do to support the struggles of democrats, workers and LGBT people in Iran, and the belligerence of our own hypocritical leaders is often fodder for clerical hardliners.

It is also worthwhile drawing attention to the hypocrisy of those western leaders for whom 'democracy' is an attack-line rather than a cast-iron principle. There will be plenty of sound and fury about Iran this week from politicians and commentators for whom tyranny and dictatorship are acceptable so long as they purport to serve 'western interests'. Those who will wax-incandescently about Iran – yet have little or nothing to say about Saudi Arabia – are a cautionary tale in thinking about states as 'blocs' and 'alliances' rather than as entities which have dominion over millions of human beings.

But this charge may also be levelled at the so-called anti-imperialist movement, the faction of the left from which Labour leader Jeremy Corbyn hails. Too often this week the protests in Iran have been greeted by either miserable silence – where are the messages of solidarity, performative or otherwise, from British trade unions or the Labour Party? – or a rather low and pedantic sort of whataboutery. 'Whatabout Saudi Arabia?' has for the most part become little more than a stock exercise in distraction – 'The people of Iran are an inconvenience. Let us instead talk about the things I wish to talk about.'

This speaks of something rotten in progressive politics, which has become so solipsistic that much of the time it operates strictly negatively. The popular motto 'Not in My Name' is the giveaway. As long as one's own hands are clean – as long as something happening in the world cannot be self-flagellatingly pinned on 'us' - it is acceptable to remain indifferent, however many corpses pile up.

This is a sorry testament to the way in which serious analysis on the left has given way to crude anti-western sentiment rooted in a peculiar - and class-bind - fetishization of anyone who points an AK47 at Britain or the United States. At the extreme end of things, materialism has ceded ground to the notion that it is the left's highest moral duty to support the ruling class of any foreign nation that purports to be 'anti-imperialist'. With a country like Iran or Cuba, this entails tacitly supporting regimes that break strikes and suppress grassroots left-wing activism.

But perhaps more depressing – the above being arguably confined to the lunatic fringes of the left - is the sullen indifference that prevails across the wider British labour movement vis-à-vis events in Iran. A grassroots struggle against the Iranian theocracy – with its deplorable combination of fake elections, brutality and sexual repression – self-evidently deserves the backing of the western left. Yet you would not put money on this solidarity being forthcoming. Instead, over the coming weeks, I imagine the plight of Iranian workers will be drowned out by sanctimonious finger-wagging at more fashionable causes – causes that will themselves go out of fashion like bell-bottomed trousers as soon as they have served their ideological purpose.

I hope to be proved wrong, though I do not expect to be. This itself probably says something thoroughly depressing about the state of much of the contemporary left.