If, on Saturday, Jeremy Corbyn is re-elected as the Leader of the Opposition, it will confirm that Labour's grassroots are completely at odds not just with their MPs but, more importantly, with the voting public. It's a position that can only end in defeat. So how did we get here and what lessons are there for all of us in politics?
The root of Labour's problem lies in its membership's response to the defeat in the General Election last year. It was unexpected amongst many Labour supporters. So they found it difficult to accept. The fact that people simply didn't like their policies or trust them with the economy, was ignored or deflected. So said it was all the fault of the media, Ed Balls or Ed Miliband. Some even said it was Tony's Blair's fault.
This denial played into the hands of the Party's left-wing. Instead of ditching policies which the public had rejected, they declared that they needed to go further. Reject Blairism and become true socialists. When Corbyn suddenly found a late slot on the ballot paper, they saw their chance, against a tired, incoherent set of more moderate candidates.
The activities of Momentum reflect the left-wing origins of many of its older leaders. For them this is about capturing the Party - setting policy, shouting down opposition, using street protests and strikes - all with the view of bringing down not just the current Government but the 'establishment'.
It's a mindset - found on the extremes of the right, as well as the left -which is all about confirming long held prejudices, rejecting all other views and blaming everyone else when it all fails. Such people are deaf to reason and regard the general public as failing to understand the issues. Like Lenin and his fellow Bolsheviks these activists regard the public as being too misguided to really understand what's going on. Seen in that context socialist kindergartens for young children may well look attractive to Momentum's members.
Yet, the last year in politics should have taught everyone a very different lesson. Whatever our own views, we should always pay close to attention to why people vote, especially when they vote differently to ourselves. As someone who voted to Remain in the EU, I have certainly learnt that lesson, both to heed the decision and understand the underlying reason for it.
Put simply the public are always right. Even when they're wrong.
Labour's grassroots aren't the first to ignore this simple truth. In the late 1990s my own party failed to understand just what the public really thought of us. We found it difficult to adjust and stayed out of office for 13 years.
It's the same in the USA where the Republicans have similarly failed to adjust and have paid the price for over a decade. For the brutal truth is that when political parties fail to heed what the public is telling them, the result is always the same. Defeat.
So, on Saturday, if Jeremy Corbyn wins, it will signal that its membership simply doesn't accept why it lost the 2015 election. Nor, why it's made losing the next one, even more likely.