Ethiopia''s national security policy goal has always been coined with the preservation of vital national interest of ensuring the survival of the state. However, its national security was threatened by external security threats from time to time, which are political and military in nature. So, it is rational for Ethiopia to recognize the realist view of the need for building defence capability to deter potential security threats before they choose to launch attacks on Ethiopia, or to defeat them in short time if they go to war. Political conflicts between the government and anti-government groups gave opportunities for hostile states to pose security threats on Ethiopia. As political threats, hostile states had provided the groups with military and political supports when they felt that they were at odds with Ethiopia. The country had also been at the center of the regional security complex of the Horn. Moreover, its neighbors were often found to threaten Ethiopia''s national security when they chose force to solve their disputes with Ethiopia. So, that is why the country has been building its defence capability to deter and/or defeat external threats on its vital national interests.