What is left to say about Labour and anti-Semitism? The row is back in the headlines again after Chris Williamson, the Derby North MP and Corbynite ultra-loyalist, is under fire for signing and sharing a petition calling for the Islington Assembly to rescind its ban on Gilad Atzmon, a jazz saxophonist who has blamed the Grenfell Tower disaster on “Jerusalemites”, and who has been condemned as an anti-Semite by organisations as politically varied as Jews Against Zionism and Hope Not Hate.

Williamson has claimed that it was only after sharing the petition that he learnt that Atzmon is “not confined to the jazz world”, a claim that for many stretches credulity as the opening paragraph of the petition is “Islington Council in London has decided to prevent Gilad Atzmon from performing with the Blockheads on 21 December. This outrageous decision by the Council was in response to pressure from a single ardent pro-Israel campaigner who said he would not attend the concert if Gilad is on stage”. One wonders why Williamson believed that there had been a complaint at all.

But the Labour leadership has accepted his account of events and the call from the Jewish Labour Movement and the Board of Deputies of British Jews for Williamson to lose the whip will go unheeded. The continued indulgence of Williamson is a running sore as far as relations between Labour and the bulk of British Jews are concerned, a visible sign of a leadership that does not take their concerns seriously.

But the Williamson saga in particular is emblematic of another and undercovered weakness in the Corbyn project. The one thing that no-one can seriously dispute is that Williamson’s continued membership of the Labour party is a drag on the party ticket. The damage is partly electoral, in that if Labour had done as well among British Jews as it did even in its 2010 defeat in 2017, it would probably have gained enough additional seats to form a minority government, albeit in a position where Labour was still well short of being the largest party. But it is also an opportunity cost, in that every time the problem hits the headlines it distracts from the party’s messaging.

Yet Jeremy Corbyn has not thrown Williamson overboard. It is hardly unprecedented for leaders to dismiss even the ultra-loyal to deal with a political problem, but it is also par for the course that Corbyn didn’t. Jeremy Corbyn’s political proximity to Williamson and his sense of loyalty to those who have stuck by him both make it highly unlikely that Williamson will ever lose the whip in any case.

As a result, in the shadow cabinet, it doesn’t matter if you are setting out striking and transformational policies like Rebecca Long-Bailey, or simply pledging a better-funded version of the status quo like Richard Burgon. You are safe in your job because you have been “loyal”, regardless of if you are actually forming new policies or causing political damage as Williamson is.

It’s not enough if you want to actually be a transformational government to have policies that work on paper – you have to have a ministerial team that has the ability to drive them through and the willingness to move people around when that isn’t working. Diane Abbott has thought very deeply about the institutional problems at the Home Office and has a number of policies that would, if successfully enacted, change the way that people who come into contact with that department are treated for the better. We won’t know unless Labour take office if she also has the skillset to drive those changes through a hostile department, but anyone who wants change at the Home Office had better hope so, because we can be certain that if she isn’t, she will still be in that job regardless.

David Cameron had the same affliction as Jeremy Corbyn and that is one reason why outside of education, his government achieved very few of its aims in policy terms. Transformative governments don’t just have to move people around who have failed to come up with new ideas – not everyone who is successful at forming policy in opposition is good at driving them through in government. (Take, for instance, the rolling disaster that is the Universal Credit.)

That Corbyn won’t move the loyal even when it is so transparently in his interests to do so is one reason why it feels likely that any government he leads will, like Cameron’s, look back at a record of achievement that fell far short of what it hoped for.