I thought it through, and it's actually dubious. I think the problem might be proportionality-- the reasoning would go something like: they could have told the

I thought it through, and it's actually dubious. I think the problem might be proportionality-- the reasoning would go something like: they could have told the Germans not to let the gas through, and that would have achieved the same effect without violence/destroying civilian infrastructure, so the attack wasn't permitted, or they achieved only a mild military advantage, since the gas could be exported through Azerbaijan, Georgia and Ukraine itself, so it wasn't permitted, and the more I think about it the more I think it actually wasn't.