Just as in the long run Pearl Harbor was a blessing for world peace at the expense of American lives, so too might 9/11/01 be seen, fifty years from today, as a "blessing" in that it finally mobilized the "sleeping giant" the destruction of the enemies of freedom.
I know that sounds a bit cold, with bodies still being recovered, but when the mourning is over, and the realization begins, I really think this is how it is going to be seen by those who have eyes to see.