The ensuing war and dismantling of Saddam's government plunged Iraq into chaos, resulting in years of deadly sectarian violence and the rise of al Qaeda in Iraq, a precursor of ISIS. Tens of thousands of Iraqis, more than 4,000 U.S. troops and 179 British service members were killed in the lengthy conflict. As the most high-profile foreign ally of former U.S. President George W. Bush in the Iraq invasion, Blair has found his legacy overshadowed by the war, with questions and criticism following him wherever he goes. Admits partial responsibility for ISIS rise Blair acknowledged to Zakaria that there are "elements of truth" in the view that the 2003 invasion of Iraq was the principle cause of the rise of ISIS. "Of course, you can't say that those of us who removed Saddam in 2003 bear no responsibility for the situation in 2015," he said. "But it's important also to realize, one, that the Arab Spring which began in 2011 would also have had its impact on Iraq today, and two, ISIS actually came to prominence from a base in Syria and not in Iraq." More broadly, Blair said, the policy debate on Western intervention remains inconclusive. "We have tried intervention and putting down troops in Iraq; we've tried intervention without putting in troops in Libya; and we've tried no intervention at all but demanding regime change in Syria," he said. "It's not clear to me that, even if our policy did not work, subsequent policies have worked better." Asked by Zakaria how he feels about being branded a "war criminal" for his decision to go into Iraq, Blair said he did what he thought was right at the time. "Now, whether it's right or not, that's for -- everyone can have their judgment about that," he said. Blair's interview with Zakaria comes ahead of a special program, "Long Road to Hell: America in Iraq,"