I really hate arguments of this form, but it seems to me that you need to give Tony Blair credit for at least having the courage of his convictions in taking on this thankless and doomed to fail task as special envoy to the Middle East. At the moment, his record is largely composed of good things, plus a giant Iraq-shaped stain. To basically double-down on the Mideast-related aspects of his legacy is gutsy.
Gutsy, but also kind of dumb. Not totally unlike risking his legacy on Iraq in the first place.