A few years ago, a popular movie named “Glory” chronicled the experiences of some African American soldiers who fought in the Civil War.

At the beginning of the war, President Abraham Lincoln refused to allow black men into the U.S. army. Many people – including Lincoln’s military advisors – believed that people of African descent were incapable of fighting in an armed conflict.

Black soldiers, they believed, would not follow orders, they would not be brave under fire, and they were not disciplined enough to be part of a force in which discipline and order were crucial.

After several months, h...