A state of emergency is a governmental eclaration that may suspend certain normal functions of government, may work to alert citizens to alter their normal behaviors, or may order government agencies to implement emergency preparedness plans. It can also be used as a rationale for suspending civil liberties. Such declarations usually come during a time of natural disaster, during periods of civil unrest, or following a declaration of war (therefore, in democratic countries many call this martial law, most with non-critical intent). Justitium is its equivalent in Roman law.