" it seems to me that one of the truths about history that needs to be made clear to a student or to a reader is that nothing ever had to happen the way it happened. History could have gone off in any number of different directions in any number of different ways at almost any point, just as your own life can. You never know. One thing leads to another. Nothing happens in a vacuum, Actions have consequences....

And just as we don't know how things are going to turn out for us, those who went before us didn't either. It's all too easy to stand on the mountaintop as a historian or biographer and find fault with people for why they did this or didn't do that, because we're not involved in it, we're not there inside it, we're not confronting what we don't know--as those who preceded us were. "

― David McCullough , The American Spirit: Who We Are and What We Stand For