Twenty years ago, as a new and enthusiastic Labour MP, I wrote an article for The Observer in praise of spin. I argued that if citizens are to be properly informed and engaged in their democracy, politicians - and in particular Governments - have a duty to craft their messages carefully and communicate them cogently. It was a controversial notion then but less so now that we have entered the era of post truth politics. In the old days, we used to 'manage' the truth. Now we have abandoned it.
We've probably come further than we think for when truth is discarded, reason generally follows. Without a general acceptance of the broad 'facts' of any matter, there can be little basis for rational debate nor, therefore, for either the consensus or the respectful disagreement which should emerge from it. Without a commitment to truth, we are free to choose and believe in our own facts and to despise the facts of others. We are free too to place our faith in leaders who make the impossible seem possible.
We condemn the dictatorships which deny their citizens the right to informed and open debate. But in our own societies, unreasoned and often irrational politics are entering the mainstream.
The Politics Of Unreason
In the UK, the Leave campaign blithely wedded brazen falsehood to the fantasy that Brexit would cure all ills - and millions of voters enthusiastically suspended their disbelief. "We want our country back" was a potent slogan - but no less vacuous than the pledge to "make America great again" on which Donald Trump has founded his election campaign. On both sides of the Atlantic, people want to take back control they know they never had nor ever will.
Both campaigns have deliberately bypassed rational argument. They play instead to the emotional response of angry people for whom reason no longer makes sense. Since the time of Plato and Aristotle, democracy's critics have warned of the ease with which reason can be subverted and citizens seduced by the false oratory of charismatic leaders. Trump is just the latest in a long line of the demagogues they feared. He may not make it to the White House but he has come a long way on unreasoning rhetoric - and where he leads millions faithfully follow. He has boasted that he could commit murder on Fifth Avenue without losing votes and he may well be right.
But if Trump is extreme, he is not exceptional. He is a phenomenon of a populism of both right and left which has once more begun to challenge the principles of Parliamentary democracy.
Democracy In Decline
All over Europe and the United States, consumer-citizens are exasperated by democracy's failure to meet their demands as fully and as fast as they expect. If the market can guarantee next day delivery, why can't government? The low esteem in which elected politicians are held is only partly the consequence of their failings and failures. It is also evidence of a growing disenchantment with representative democracy itself. We do not trust our politicians to reflect our priorities. Perhaps we never did. But now we're no longer prepared to acknowledge their unenviable duty to arbitrate between competing political, social and economic imperatives, nor ours to accept the compromises they reach - at least until the next election.
We have become protesters against rather than participants in our politics and, emboldened by hearing our chosen facts and beliefs reverberating around cyber space, have become increasingly polarised and uncompromising in our protest.
Politics Without Purpose
Which brings us to Labour. Despite the obvious political differences between Jeremy Corbyn and Donald Trump, there are striking similarities in the movements which have coalesced around them. For many of their supporters, they can simply do no wrong; each criticism provides further evidence of a corrupt establishment's conspiracy against them; rivals, including those who share many of their beliefs, are anathematised; unbelievers are pursued across the internet; inconvenient facts are reinterpreted or ignored; rational, civil debate is shut down or drowned out.
There are other similarities in these insurgencies: both mistake slogans for policies and mass rallies for popular support; both are overwhelming and quite possibly destroying their own parties - and both, ultimately, are movements without practical purpose.
Trump may give vivid expression to his followers' grievances but, other than building a wall along the Mexican border, his plans for government are obscure. Similarly, while Corbyn and his supporters know what they're against, they have not yet articulated a clear vision of what they're for, much less how it can be achieved. For many of them, it is enough to be 'anti-Blairite'.
But in disassociating themselves from a Labour Prime Minister's mistakes, they are also dismissing their party's achievements under his leadership. Their refusal to acknowledge the need for compromise may well enable them to avoid the pitfalls of government. But government's potential to bring about at least some of the change they want does not come without pitfalls. In wanting it all, they are likely to end up with nothing.
Rediscovering Common Cause
Democracy cannot be sustained simply by what passionate people oppose. And though movements such as Momentum have important roles to play in influencing political parties, they cannot replace them. Their supporters want to be right - and they often are. But they are rarely prepared to test their principles against the practical business of government. The members of political parties want, or should want, to govern and are prepared, albeit reluctantly, to compromise - with each other, with those they seek to represent, with events - in order to do so. Parties should listen to movements. But movements, if they are to have any practical purpose, must acknowledge that, for all its limitations, the point of politics is power.
We have to trust that the majority of American voters will reject Donald Trump. But closer to home, if Labour is to have a future as a political force, Jeremy Corbyn's supporters must learn to respect the historic purpose of the Labour Party at least as much as they admire the high principles of its current leader. There isn't long for that realisation to take hold.
In the UK as in the US and elsewhere, we need to rediscover the importance of common cause and the art of compromise in forging it. The alternative is a form of politics which is not only post truth, post reason and post purpose but also post democratic.