He's a smart man, I don't believe he believes it was God's work - I think he was sending that message out to our own nutty Judeo-Christians, as well as those on the other side of the Atlantic, in justification and support of what he and GWB had done -- not just to keep them on side, but also so he'd have a captive audience for his little lecture tour he did a while back.
I think he knew that unilateral war was a vote loser, and I'm certain he knows it now - but he gambled on the Atlantic alliance being more valuable than the European one. He
met Clinton repeatedly for advice and Clinton wrote this op-ed for the Guardian
asking Labour MPs and the public to trust his judgement. Ultimately, I think we softened the diplomatic fallout that the US would have caused by going in without us because we thought that would be the 'best' thing to do in the circumstances. In 50 years, we'll probably learn that we were promised things, material benefits, for going along with it. I don't think that it was the right thing to do, but the US hawks were going in, and all our efforts at the UN brought was a televised statement from Jaques Chirac saying he would support no further resolution that authorised war... the French, Germans and Russians weren't exactly clean or trustworthy at the time, each of them were knee deep in contracts with the ba'athists.
All the shit about legacy is tabloid narrative imo. The papers and the public are so keen to believe things like that, but I don't believe it would have been so simple. Civil servants and generals don't stand idly by and let a PM drag them into a war to further his own legacy, there was ambivilance about it from the beginning and tacit support in some quarters...
I find it interesting that the anti-war protestors outside are also tying Afghanistan to him as though he did something wrong there... again, I think that's just wilfully blind hatred compromising what they are trying to do. At the time, NATO action was unquestioned. We'd just had 9/11 and an attack on one is an attack on all... Tony Blair was supposed to not go into Afghanistan when every other NATO power did?