In the post–World War II era, the UN Charter prohibits signatory countries from engaging in war except: 1) as a means of defending themselves—or an ally where treaty obligations require it—against aggression; 2) unless the UN as a body has given prior approval to the operation. The UN also reserves the right to ask member nations to intervene against non-signatory countries that embark on wars of aggression.
In the post–World War II era, the UN Charter prohibits signatory countries from engaging in war except: 1) as a means of defending themselves—or an ally where treaty obligations require it—against aggression; 2) unless the UN as a body has given prior approval to the .operation. The UN also reserves the right to ask member nations to intervene against non-signatory countries that embark on wars of aggression