Casus Belli - Reasons For Use

Reasons For Use

Countries need a public justification for attacking another country. This justification is needed to galvanize internal support for the war, as well as gain the support of potential allies.

In the post World War Two era, the UN Charter prohibits signatory countries from engaging in war except 1) as a means of defending themselves against aggression, or 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 which embark on wars of aggression. In effect, this means that countries in the modern era must have a plausible casus belli for initiating military action, or risk UN sanctions or intervention.