What is a 'declaration of war' and when was it last made

A declaration of war is an ancient diplomatic ritual in which one party announces a complete cessation of peaceful relations, a break in direct diplomatic ties, and the commencement of hostilities. It is so ancient that it is mentioned in the Old Testament and in Sumerian writings. It seems that declarations of war were the norm in previous centuries, but this is far from the truth: between the 17th and 19th centuries, only ten wars were officially declared. Among these ten declared wars is the well-known invasion of Russia by Napoleon in 1812. In 1907, the Hague Convention was adopted, establishing a standard procedure for declaring war. In addition to the parties involved, neutral parties must be notified of the beginning of hostilities. Before declaring war, the last warning with justification or an ultimatum must be communicated to the opponent. The last large-scale war in which the tool of declaring war was actively used was World War II. Germany did not particularly care about this, while Japan diligently prepared and delivered documents through diplomatic channels on the day of the attack on Pearl Harbor. Almost all allies entering the war against Japan also officially declared war on the islands, including the USSR on August 8, 1945. After World War II, the ritual of declaring wars was practically shelved. This was largely because the UN Charter significantly limited the acceptable military justifications under international law. Wars themselves, however, did not disappear, as you well understand. Nevertheless, Israel and the Arabs regularly resorted to the tool of declaring war during their countless conflicts. The Iran-Iraq War of 1980 also received an official declaration. Additionally, some local conflicts, mainly in the African region. On the world stage, the last recorded declaration of war by one country against another was in 2020. On November 14, the Sahrawi Republic announced this to the Kingdom of Morocco. There have also been humorous cases. In 1975, the mentally unstable dictator of Sudan, Idi Amin, declared that he was declaring war on the United States of America. And since the Yankees did not respond and did not show up for the war, Idi Amin reported the next day about his crushing victory, as reported by the magazine 'Maxim'. Read about the modern catastrophe in Sudan [here](https://bb.lv/statja/v-mire/2026/10/27/milliony-liudei-na-grani-goloda-latviia-i-eshhe-30-stran-biut-trevogu-iz-za-katastrofy-v-sudane)