"I don't rule out the possibility that in a situation of armed working-class resistance to, say, an occupation it might be necessary to attempt to reach military/tactical ententes with a force like the Mahdi Army."
Exactly. You then come up with, virtually repeat from me as it happens, several arguments why in this case there almoast certainly couldn't be such a united front. Again I agree (in fact I said it myself)- which is why I posted our understanding of the anti-imperialist united front that explicitly says, "Nine times out of ten, where there exists no especially favourable relation of forces or political situation, the reformist or nationalist leaders will refuse it."
Even this is in the situation where rank and file workers have illusions in these nationalist forces- it is not really the situation that organised workers in Iraq do. However, some less politicised workers- not organised in unions or as workers but hating imperialism and the occupation- clearly do have illusions in the Mahdi Army. To them we should say, I suggested, "If you think Sadr is fighting imperialism you are entirely deluded. He plays into their hands. Only the working class can defeat imperialism. if you think he is genuine why not ask him for arms to fight imperialism? But we tell you now he will not only not give you arms but you will need to defend yourself against his vicious thugs. Do not trust him or his Islamist militias for one second- that way lies death and ruin! Instead arm yourselves and break from Sadr and all other bourgeois misleaders!"
On whether my view that we should support HOPI's position of a nuclear-free Middle East and be for the working class in Iran oppose Iran having nuclear weapons as we haven't voted on it I really don't know whether it would be a minority position or not. It is a reasonably complex issue that doesn't fit schemas and PR unlike the previous organisation and many on the left think through issues. On many matters- like say supporting, "Troops Out Now!" or for strike action and any direct action possible against an attack on Iran I know the majority and almost certainly unanimous PR position. There may be some other positions I'm less than sure on- e.g. nuclear power. I think it would be a slim majority position for a workers' enquiry, workers' control, in which we'd argue for publc safety as a paramount concern, carbon neutral energy. Another view I guess of a slim minority would be to say close them now. We can have- as you say- different views in an organisation as long as they don;t undermine common actions.