In 1098, the armies of the First Crusade were besieging the city of Antioch. One of the commanders, Etienne Henri Comte de Blois (Count Stephen Henry of Blois as English historians style his name), abandoned the army and fled back to France.
On his way, he encountered the armies of the Byzantine emperor Alexios Komnenos and told him that the Turkish forces were too great. Alexios, with no reason to doubt a French nobleman, did not advance further.
Eventually, the Crusaders took Antioch and repelled an attack by the Turks under Kerbogha – without Byzantine help. The failure of the Byzantines to relieve them created an animosity between the French and the Byzantines that would eventually culminate in their sack of Constantinople a century later in 1204.
Ironically, it was a Frenchman – Etienne Henri – who had prevented the Byzantine army from coming to the Crusaders’ aid.
One man did not believe in the cause, and as a result, he helped breed distrust among people who should have been allies and helped open a wound that still festers today.
Of course, the Crusades were a bloody affair and I am not advocating religious war; but it seems that if one commits to a course and others are depending on him, then you have a duty to both yourself and others to see that course through.
It is easy to surrender and call it practicality, to strike the colors of a cause you said you believed in and call it compromise. Remember, you never know who you will impact and how long that impact will echo in their lives.