The truth is you have no way of knowing, so there's very little point arguing about it. Personally I think people will look back at the huge success of the Labour Government under his premiership. Iraq or not he remains the only person to lead the Labour party to three consecutive general election victories. That's his legacy, every bit as much as Iraq.
Blair transformed Britain forever. Same sex-marriage, new maternity rights, the Equalities Act, adoption leave, new schools, a new hospitals programme, new builds getting access to brownfield sites, surestart... he also played a major role ending a centuriues-old conflict in Northern Ireland. Now I'm not saying the guy was the second-coming, clearly he had his faults, but I'm so bored of reading about "B.Liar" and his depiction of the devil incarnate - don't forget he was democratically elected as our Prime Minister even after the Iraq invasion. So if you want to talk about it, talk about it - but please let's leave the lazy charactuer-driven bullshit to one side. Isn't discussing a flawed human being infinitely more interesting?
Iraq was a total, unmitigated disaster. There's no doubt about that - but it did bring Iraqi democracy. Is there instability? Yes. Jesus Christ is there. It's awful seeing the news sometimes. And was it caused by Blair and Bush? Partly, yes. The reconstruction and exit plans were disgracefully shortsighted but that doesn't change the fact that the forces behind the Arab Spring, which have torn Syria apart, would have no doubt happened in Iraq if Saddam had stayed in power.
/rant
Would trend to think of this more as huge success of the Labour Party, rather than the Labour Government,. No doubting he did an incredible job to take what was an unelectable rabble and transform it into something that lasted as long as it did with his rebranding. Whether it was a successful government is more debatable........