What is the importance of the battle in Dien Bien Phu in the novel, The Ugly American?

The battle in Dien Bien Phu is important because it serves as a symbol of the larger struggle between invading Communists and the Western forces that try to protect the natives. The natives are themselves divided in their loyalties, so their allies fight in vain. The Vietnamese hate their French allies more than they fear the Communists. The Communists have already infiltrated the village long before the battle, so the allies are shocked and unprepared for attack from all sides. The French lose the battle because they completely underestimate the intelligence and tactics of their enemy.