Casus belli

Casus belli is a Latin expression generally used to indicate the act or fact which can become cause for a war.

The expression can however be translated in slightly different ways:

• This is the case, the opportunity for a war;
• This is how things go during a war, a typical consequence of war (casus can also mean "accident", "casual event").

Like for many Latin expressions, this one too is sometimes used not properly by politicians or journalists for instrumental purposes, while it is more often correctly found in historical works, when describing ex post those events which effectively led to a war.

Today casus belli is also used to indicate a genre of role-playing games and computer wargames.

See also:

• Latin phrases - Latin proverbs - Latin language
• war
• wargames