For several years, I drove past the signs directing me to the Flight 93 Memorial in Shanksville, PA, the site where one of the doomed airliners was driven into a barren field by passengers who knew that the fate of the United States government possibly lay in their hands. Hurried calls on the morning of September 11, 2001 from some of the passengers on UA93 to loved ones had alerted them to the fact that they were part of a terrorist plot…