The usefulness of events with zero probability of occurrence

Two statements from Dubya about what it would take to draw action from him:

[on 9/11 advance warning] Had I known that the enemy was going to use airplanes to kill on that fateful morning, I would have done everything in my power to protect the American people

[on his attitude to Vietnam and the draft] Bush said he supported his country during the Vietnam War, but called the conflict "a political war."
"I supported my government," he said. "I did. And would have gone had my unit been called up, by the way."