Simon Wren-Lewis says that, faced with the prospect of a Johnson-led government, Jeremy Corbyn is the lesser of two evils and should therefore be supported. I tend to agree, but with two caveats.

One is that we cannot dismiss Labour's problem with antisemitism. True, nothing Corbyn has ever said is as overtly obnoxious as Johnson's talk of "picaninnies" or that Irishmen are all called Murphy. The evidence for his antisemitism consists in a deafness to anti-semitic tropes; a failure to call it out when he should; and a closeness to the sort of moralizing conspiracy theory that can spill over into antisemitism.

Mild as they are compared to Johnson's racism, however, these are genuine failures. For obvious reasons, Jews are rightly awake to tail risk - the tiny chance of genuine hostility. If even one Jew is made to feel sincerely uncomfortable by the possibility that a Labour government even might be antisemitic, that is abominable. And it is an indictment of Corbyn.

My second caveat is that I don't think Simon, or many leftists, are drawing the right inference from a wholly correct observation - that the media is horribly biased.

True, Labour's antisemitism is being overplayed and Tory Islamophobia understated. True, some of those accusing Labour of antisemitism are gross hypocrites who were happy to acquiesce in subtle antisemitic slurs on Ed Miliband. True, there is no equivalence between the gibberings of a few twats in Labour and the overt and systematic racism of the Tories' "hostile environment" policy.

True, true, true,

And irrelevant. Labour faces the same problem as football team when the referee is bent. Its mild infractions are penalized whilst its opponents can get away with serious fouls.

But what should a team do in such circumstances? Complaining would energize its supporters. But the ref will deny his bias and book players for dissent. Complaints won't win the game.

Instead, what the team must do is to be cleaner than clean. Its only hope is to not make any risky tackles which give the ref an excuse to award penalties. As my old dad said, "never give a cunt a chance to be a cunt."

And this is what Labour has failed to do. In failing to ruthlessly expel anyone even whiffing of the possibility of antisemitism, it has given its enemies something to exploit: the need for Labour to win an election trumps anybody's right to be a member of it. This might be a moral failure, but it is certainly a horrible tactical blunder.

All of which raises the question. Is Simon right to say the only choice is between Johnson and Corbyn? But could we do better? Could we have a radical Labour party without Corbyn and his public school Stalinist entourage?

Many decent leftists are cleaving to Corbyn in the fear that throwing out the fetid bathwater of antisemitism would also mean abandoning the (so far half-formed but nevertheless inspiring) prospect of a genuine alternative to actually-existing capitalism and retreating back to managerialist defences of inequality. I honestly don't know how justified this fear is, although it is troubling that too few of Corbyn's critics are striving to allay it. And whilst this fear exists, Simon is right: Corbyn is the lesser of two evils.