When Sir Keir Starmer was elected Labour leader he said his aim was to unify his party and rebuild trust with the Jewish community.
The decision he took on Wednesday saw him pursue one of those goals at the expense of the other.
By upholding the suspension of Jeremy Corbyn from the parliamentary party, despite Labour’s governing body reinstating his predecessor’s membership, Sir Keir knew he was likely to reignite a factional civil war.
That he pressed on with that option anyway says a great deal – he judged the alternative to be far more politically incendiary and damaging longer term to his prospects as leader.
The fact the Jewish Labour Movement, the Board of Deputies, the Jewish Leadership Council and Community Security Trust had all so clearly expressed their outrage at the NEC’s decision meant Sir Keir was able to argue the Jewish community did not have confidence in the disciplinary process and that therefore he would use the power left available to him and demand the whip be withheld.
But it was by no means just pressure from Jewish groups that led to the decision.
I understand individuals who had worked right at the heart of his leadership campaign just a few months ago on Tuesday night threatened to leave the party in protest over the NEC’s handling of the case.
There was the possibility of resignations from the shadow cabinet, and some Labour backbenchers leaving the party altogether.
Why would he risk all that in order to prevent a backlash from a wing of the party who have already made clear their loyalties are split?
Corbyn allies’ fury at decision to block ex-leader returning as Labour MP
So far the reaction from Mr Corbyn’s allies has been furious, but it is not obvious they intend to take things further.
Former shadow cabinet ministers from the Corbyn era like John McDonnell and Diane Abbott have warned further disunity and division will follow, but suggestions that key figures could split off to form a new left-wing party have so far not shown any signs of materialising.
The most strident voice of criticism so far has been from Unite boss Len McCluskey who issued a blistering warning, saying: “I urge Keir Starmer in the strongest possible terms to pull back from the brink.”
Given Mr McCluskey has already moved to reduce some of the funding Unite provides to the Labour Party, this will no doubt be seen as a threat that more may be to come, but for now that threat hangs in the air.
One part of Sir Keir’s statement that is concerning those close to Mr Corbyn is the final line, in which he said: “I have taken the decision not to restore the whip… I will keep this situation under review”.
They claim this limits their options to challenge the decision because it implies it’s not a final decision, and yet they have no idea what would be needed to change it.
That indicates once again the wider issue of antisemitism and the party’s handling of it is going to be fought via the differing interpretations of the party rule book and rows over disciplinary mechanisms.
Even when an independent complaints process is eventually introduced, it’s unlikely that a particular characteristic of Labour internecine warfare will disappear.