Jeremy Corbyn’s difficulty in carrying his parliamentary colleagues with him in his opposition to bombing in Syria will be seen by his supporters as a decent man struggling to reconcile his deeply held principles with the exigencies of political leadership, in a society that is easily persuaded that action counts for more than reason. Others, no doubt, will see his willingness to alienate centrist opinion on this and other issues as further evidence of his unfitness to lead.

Even those who wish him well, however, will recognise that, after a lifetime of endorsing minority or unpopular causes, bombing in Syria is just one of a number of similar issues, each of which will run the risk of further eroding his precarious support in the parliamentary party, encouraging further outrageous attacks on him from the rightwing media, and discomforting even some of those who voted him into the party leadership.

A realistic assessment, in other words, would lead to the conclusion – welcome or otherwise, according to taste – that whatever views he may hold on Syria or on other issues of the day, there is a growing possibility that he might never have the chance to put them into practice. He could tire of the struggle and decide that the game is not worth the candle; or his many opponents in the parliamentary party could find a way to depose him; and, even if these possibilities do not eventuate, their mere existence will shorten the odds against his leading Labour into government at the next election.

If any one of these outcomes were to materialise, it would be celebrated in many quarters, not least by those who would leap at the opportunity to proclaim that a Corbyn demise meant that everything he stood for had been discredited. But in that event, those who found much to support in his leadership election campaign would need to ensure that what Corbyn had to say on the most important issues, and that stimulated such a positive response, was not thrown out with the bath water.

It may be necessary, in other words, to distinguish between the man – Corbyn, with his own political baggage and at times idiosyncratic positions – and the message, the message that he articulated and that resonated with tens, perhaps hundreds, of thousands of those who had given up on politics.

That message was clear. There is an alternative – a real and viable alternative to the current orthodoxy of austerity, of giving priority to cutting public spending, of widening inequality, of piling burdens on the most vulnerable. It was this brave assertion that propelled him into the leadership and that opened up a long overdue debate. It is a message that could and should have been delivered long ago by his rivals for the leadership and by his current opponents in his own party.

Their dereliction of duty meant that it fell to Corbyn to deliver it. That he seems alone in doing so is an indictment of others rather than of him. Whatever may be the deficiencies of what he might say on other issues, what he had to say on the central question of politics – who runs the economy and in whose interests? – was right on the money.

There is a rapidly emerging consensus that – as we discovered 80 years ago but then forgot – austerity is the wrong response to recession. We are learning that lesson all over again. Even in terms of its own stated objectives, austerity has failed; the supposedly central priority of eliminating the government’s deficit remains a long way from being achieved, while the deficit that really matters – the country’s continuing failure to pay its way – remains unattended to and is getting worse.

In the meantime, poverty and inequality increase, housing is increasingly unaffordable, net investment is virtually zero, the prospect of a revival in manufacturing is non-existent, and an unsustainable consumer boom fuelled by asset inflation underpins our rake’s progress to decline.

Corbyn’s assertion that it need not be like this, that government’s responsibility is not to focus on cutting its own spending but to get the economy moving again in a productive direction, that growing poverty and inequality are barriers to economic efficiency, that we must invest in new productive capacity if we are again to pay our way in the world, that full employment is the hallmark of a properly functioning economy, is endorsed by a growing number of economists and others who are now prepared to stand up and be counted.

On this issue, in other words, Corbyn is far from isolated. On the contrary, his message is gathering force. He points the way to government accepting its true responsibilities, and to policy and action that are increasingly recognised as essential for our economic future. If his opponents in his own party turn back to their longstanding and virtually inexplicable acceptance of a failed neoclassical orthodoxy, they will – unwittingly perhaps, but because they are obsessed by day-to-day political infighting – have closed their minds to their true responsibilities. What is at stake is more than the political fortunes of one man, but the chances for both party and country of finding a way out of their long trough of decline.