The torture debate is critical not only because it gets us to the core of our values, but because the danger to American cities is not from tanks and armies, but from individuals and their intentions. Saving thousands of American lives may come down to the gifts of a talented interrogator and the tools at his or her disposal. Remember that usually only in the movies does a prisoner spill the beans on an upcoming plot. As interrogators will tell you, information about terrorist activities tends to come in fragments that are assembled from scores of interrogations, even as the truth is distilled—accidentally almost—from a spewing forth of lies and subtle evasions. The front line of our defense against al-Qaeda and its offshoots is painstaking, tedious work that rewards those best able to fill in the blank spaces from a shattered jigsaw puzzle.