expansionism

thumb|The full extent of the empire of Alexander the Great, assembled in the 4th century BCE as he strove to conquer the lands of Asia and the Mediterranean Expansionism refers to states obtaining greater territory through military empire-building (e.g. imperialism) or colonialism. In the classical age of conquest moral justification for territorial expansion at the direct expense of another established polity was often as unapologetic as "because we can", treading on the philosophical grounds of "might makes right".

As political conceptions of the nation state evolved, especially in reference to the inherent rights of the governed, more complex justifications arose. State-collapse anarchy, reunification or pan-nationalism are sometimes used to justify and legitimize expansionism when the explicit goal is to reconquer territories that have been lost or to take over ancestral lands. Lacking a viable historical claim of this nature, would-be expansionists may instead promote ideologies of promised lands, perhaps tinged with a self-interested pragmatism that targeted lands will eventually belong to the potential invader anyway.