What I remember most about serving with the U.S. Marine Corps in Iraq was realizing the extraordinary level of hatred that the Sunnis and Shia Arabs had for each other.

To understand Iraq today, one must understand the deep religious divisions within the country. The Islamic faith fractured into two very separate sects following a leadership struggle after the death of the Prophet Muhammad in 632 A.D. Muslims who believed that the leader should be one of his descendants became known as Shia while those who believed that the leader should be decided by the community of Muslims became known as Sunnis.