That's a bit harsh on the greatest (and only!) Labour PM in recent history.
Blair will of course be remembered as the UK PM who finished the work started by Gladstone and, with Clinton and Ahearn, brought peace to Northern Ireland. Furthermore, he (with Clinton) persuaded NATO to bomb Serbia in 1999 to stop ethnic cleansing in Kosovo and Bosnia (while the EU stood aside); sent UK troops to Sierra Leone to prevent a civil war; and participated in the US attack against Al Qaeda in Afghanistan. All clearly ethically justified.
The intervention in Sierra Leone would appear to have been an unqualified success. In Kosovo and Bosnia less so in my opinion, but undoubtedly the people of the Balkans are better off now than if Mikosevic had been allowed to go on unchecked. I think Blair came to a naive belief in his own powers after this which lead him to the quagmire that was Iraq.
As for the US intervention in Afghanistan, while the initial intervention was certainly justified, the disaster the followed nullifies that in my opinion. Had they just overthrown the Taliban and gone home.