War is failure of diplomacy.

The aphorism frames war not as an inevitable instrument of statecraft but as evidence that political leaders and institutions have failed at negotiation, deterrence, and conflict resolution. By calling war a “failure,” it implies that diplomacy is the preferred and more rational means of pursuing national interests, and that resorting to armed force reflects breakdowns in communication, trust, or imagination. The line also carries a moral critique: the human and material costs of war are presented as avoidable consequences of earlier mismanagement. As a political maxim, it encourages investment in diplomatic capacity and warns against treating military action as a first resort.