Whether or not he came to believe it - so many people, when they have a mission, come to believe something in a way that may have started out as a slogan. You know, L. Ron Hubbard, not to make a random comparison, started Scientology as a scam.
The funny thing about being Catholic, and I was raised Catholic, is that you identify with the Church, just as part of your character. Nevermind what you believe, it's just who you are.
When we go to war, our politicians will be guided by our popular will. And if we believe that torture 'got' bin Laden, then we will be more prone to accept the view that a good 'end' can justify brutal 'means.'