To be clear, I'm a native US citizen and I've never lived outside the US. (Edit: I say this because you referred to me as ``YOU'', referring to Britain, which is not the case. I don't know that's what you intended, but I just want to be clear.)

My problem with individual countries taking action is still the bully problem. What if it was discovered that the US made biological weapons? And then Iran decided to attack? What would you say about it then? What would the UN say about it? (Nothing, since the US gets to veto anything it wants.)