So how do you test for courage? And how do you build it? There is a tendency to think that only courageous people will seek the job of protectors, servants of the community and warfighters for their country. This is more likely to be true when the danger of the job is apparent. A school resource officer — a law enforcement officer who is there to guard a school — is not exactly on the front lines in the war against violent criminals. But even in the case of military personnel, the number for whom direct combat is an obvious part of the job is small.

In times of peace or when only a very small percentage of the military is engaged in combat, it is easy to forget the realities. The Army has experienced this forgetfulness many times. When the military was called up for the first Gulf War, for example, hundreds of soldiers did not show up to deploy. In 2004, a fuel transportation unit refused a mission to deliver fuel because it was too dangerous. The mission was carried out by another unit, with no casualties. Although the members of the 507th Maintenance Unit — which included Pvt. Jessica Lynch, who was briefly taken prisoner in Iraq before she was rescued — did not shirk their duties, their almost complete lack of fighting skills when ambushed in 2003 reinforced the lesson: Peacetime training does not always do a good job of preparing people mentally for combat.