The support of the armed forces is a necessary condition for a revolution to succeed. The 2011 Arab uprisings support this contention. The military’s role is examined in the six Arab states where significant bloodshed had taken place: Bahrain, Egypt, Libya, Syria, Tunisia, and Yemen. They can be grouped into three categories defined by how the regular military responded to the revolt. In Tunisia and Egypt the soldiers backed the revolution, in Libya and Yemen they split, and in Syria and Bahrain they turned their guns against the demonstrators. These different stances by the armed forces largely explain the different outcomes of the revolutions.