So now we know why Tony Blair went so soon. The Sunday Telegraph tells us that secret papers show us that Blair "misled MPs and the public throughout 2002 when he claimed that Britain’s objective was 'disarmament, not regime change' and that there had been no planning for military action." They say that the papers show British military planning for a full invasion and regime change began in February 2002, which if I recall was after Blair had popped over to the US for a photo-op with George W.
Clearly, if he had hung around in parliament he would have been forced to explain his actions and matters might have gone so far as a forced resignation. But once he has left parliament, nobody cares and he is no longer answerable, so he can swan around America collecting his £150,000 a speech fees and telling everybody it is time to draw a line under the Iraq War and move on.