Invasion

Invasion is a military action, consisting of troops entering a foreign area (a nation or territory, or part of that), resulting in the invading power getting control over the area (occupation, either briefly, or for a longer period, see below). Invasion is often opposed by native resistance. Invasions may be conducted to restore or change the leadership of a nation of territory. This sort of invasion may be perceived by one side as an act of usurpation, while the other may perceive it as an act of liberation. Other reasons for invasion have included the restoration or expansion of territory, the pursuit of enemies or the protection of allies, to pre-empt an attack, to retain or gain access to transportation routes or water supplies, to quell destabilizing or unconscionable conflict within or between neighbours, and to punish a perceived sleight. The word intervention is sometimes used as a euphemism for invasion. See also: List of invasions, War