Yes, but it highlights a significant problem. Blair's party mostly consists of appeasers, and there is serious risk that they will throw him out of office over this. Probably they would not do it until after the Iraq invasion had succeeded, but, still, getting thrown out of office for siding with the US would be a bad precedent.
I remember reading Churchill explaining how at international meetings, he was the only leader who could lose his post at any time. Churchill claimed to like this, which is dubious.