Approximately 98% of all tweets sniping at left Labour members for wanting to leave the party now Corbyn has gone, AND all tweets threatening Bernie supporters with Trump if they don't vote Biden, miss the point of such principled withdrawal. <Thread.>

There is a very clear logic, which goes back to a fundamental 19th century distinction between revolutionary and reformist strands of socialism, behind both approaches. Both have their place, and I am not attempting to evaluate them in this thread - that would take forever.

All I want to do here is to offer the case for a principled withdrawal of left-voices from the main 'left' party under certain circumstances, because, as I mentioned at the beginning, such a case is so rarely made explicit.

Instead, what we tend to get is emotional blackmail from the centrist side 'If you don't support Starmer/Biden you will get Johnson/Trump forever', and bitter hyperbole from the left side 'Biden/Starmer are evil/useless/traitors', etc. Far more heat than light.

So why would someone on the left of US politics EVER vote Trump over Hillary Clinton, or Joe Biden? And given that is a rare circumstance, why would they even risk Trump winning by not actively supporting+voting for the Democratic candidate, even if it is not the one they wanted?

One argument sometimes offered by the Left is, even if often true, unhelpful - that is to make the case that a given centrist candidate is 'no better', on a given metric, than their right-wing opponent. There are three key problems with this often-seen argument.