IN 1963, writing from a jail in Birmingham, Alabama, Martin Luther King expressed his frustration with what he termed the “white moderate.”

Famously, he explained how it is not in fact the hard-right that has posed the biggest obstacle to progress, but those who insist on a doctrine of “wait.”

He denounced the false equivalency moderates have drawn between his movement demanding justice, and its strongest opponents.

This observation had already taken on new meaning in the United States in recent years, where the Establishment wing of the Democratic Party has frequently framed Bernie Sanders’s movement as a left variation of Trumpism.

Whether Joe Biden and Pete Buttigieg or Nancy Pelosi and Chuck Schumer — the message has been the same.

Of course they empathise with the spirit of Sanders’s politics — but he must wait.

The events of the last two months of British politics have taken a startlingly similar shape.

King’s complaints, despite the obviously vast differences in situation, hold true.

Last month, we were treated to the rich hypocrisy of Jo Swinson both claiming to want to stop Brexit, and refusing to put Jeremy Corbyn in power.

Brandishing centre-right austerity credentials from the Cameron days, Swinson’s own record reveals a politician firmly against any kind of structural change.

This tendency rears its head again in the willingness to engage in persistent undermining by figures on the Labour right, a la Tom Watson, Gordon Brown, or turncoat Chuka Umunna.

And it would be a mistake to view it through the narrow lens of anti-Corbynism.

Taking Umunna as a case study, in founding Change UK there was an insistence on partnering with austerity Tories and on “regulated private enterprise,” taking a strong stand against the renationalisation proposed by his former party.

This underscores a view that these ideals along with those of the broader Corbyn project are either unachievable, or undesirable.

Whatever the motivation of these political actors, the result is the same: the work of the right is achieved.

The scramble to force moderation on radicals does nothing but place progressive ideas under attack from the people who are supposed to be advocating them.

Any enlightened measure is always going to face fierce criticism from the right.

An onslaught from the centre and centre-left can finish them before they even get off the ground.

Of course, much of this is old hat. It is a truism that since birth of neoliberalism traditionally left-wing parties have held large centrist components.

Tony Blair, Bill Clinton and Barack Obama spring to mind. What remains underappreciated is the impact this had on the relative “location” of the political centre, and what British liberalism in particular has come to represent.

While historically the centre may have represented a genuine middle ground between capitalism and socialism, now it represents an obsession with “moderation.”

As the last 40 years have drifted the national conversation further to the right, this has produced a wholehearted commitment to the economic and democratic conventions of the period, good or bad.

Perceived “extremism” of any variety therefore is instantly disqualifying from the liberal-centrist point of view — whether that be an “extreme” commitment to helping the poor or an “extreme” commitment to attacking the NHS.

This is the sort of doublethink required to produce headlines such as one found in the Independent around a year ago, which proclaimed “Labour and the Conservatives are being held hostage by the … insane fringe.”

This gravitation to the right by the rest of the political landscape means that the re-emergence of a genuinely centre-left alternative in Corbyn has wrong-footed and exposed many bad-faith actors.

While the attempts to remove him from the top of the party prior to 2017’s remarkable gains may have been founded on genuine concerns about electability, those in its wake can be guided by one thing alone — ideology.

Opposing Corbyn is no tactical choice, certainly by those within his party, but a belief that losing is a price to pay for removing him.

Moderates, dressing up as the sensible ones, reject the notion of dramatic change altogether.

We are told the passing of time will correct the problem. This is no deviation or specific political play, no personal choice on the part of politicians of good conscience, but simply the nature of the parties and institutions that represent the centre in the modern day.

For all the problems this political persuasion brings with it, there is a strong argument against such sharp criticism.

Sure, the Lib Dems aren’t perfect — but why focus on a party with 15 MPs and not the revitalised Tory election machine?

There is a more compelling school of thought, however, which says that the majority of current Conservative voters are not going to switch to backing Corbyn.

This isn’t the 2000s — polarisation is back, and the Lib Dems’ socially, liberally, environmentally conscious and pro-opportunity base are natural fellow travellers to any social democratic movement.

Contrasting the Conservatives is important on many levels. It identifies the ideological enemy and shows people who to vote against.

But the bulk of these people swayed and mobilised will not be dyed in the wool Tories or Brexiteers, a solid 40 per cent of the voting population, but people who care about a fairer society.

It is important that as part of this strategy we effectively critique the inability of the Lib Dems, along with the Hillary Benns and Yvette Coopers of the world, to offer real solutions to the problems these people identify in society.

Defeating the Conservative government in any upcoming election will require an extraordinary effort and genuine strategic thinking.

A crucial mistake for the left would be to allow the Lib Dems and centrists more generally to continue to pass themselves off as a forward-thinking alternative.

This will mean that talk of voting for the Remainer most likely to win, or of Liberal-Green and Liberal-Plaid pacts, must end.

But more than that, it means exposing, as King did, the scam of the moderate and the ideology of “wait.”