What is the main purpose of the military? To deter, fight and win war both at home and abroad. As I have already outlined in the previous two blogs, Rules of Engagement (ROE) are the critical lynchpin, or key interconnecting devices, between the two separate and different political and security spheres of a nation during any armed conflict. ROE are binding political-military-legal orders given to national military forces by civilian national government officials, which clearly limit or restrict what the military can do on behalf of the nation, and in the name of the government, while actively deployed in a theatre of armed conflict. In most countries of the world, national armed forces are the military servants of the civilian masters in government. As such, and because of the changing nature and short-term tenure of governments of various and often rival political parties and ideologies, especially in liberal democratic countries, national armed forces are strictly apolitical and non-partisan. This blog will examine both the primary and secondary purposes of the military in every State, and the three kinds of wars national militaries usually engage in historically and today.