If only all countries had such a constitution! In 1946 at the end of WWII Japan was forced to sign a document that included a clause, Article 9 of the constitution. This stated that Japan renounced any sovereign right to wage war. It's aims were to be based on justice and order.
Having a constitution that makes it unlawful to wage war goes to engender the moral duty to be peaceful. Were this to be an international duty we could all progress with an easier mind.
Japan’s constitution is unique because it was drafted by the United States after World War II. Article 9 is its most unique feature because it basically prevents Japan from starting any future war and from establishing or maintaining a military force.
Specifically, Article 9 reads as follows: “(1) Aspiring sincerely to an international peace based on justice and order, the Japanese people forever renounce war as a sovereign right of the nation and the threat or use of force as a means of settling international disputes, and (2) In order to accomplish the aim of the preceding paragraph, land, sea and air forces, as well as other war potential, will never be maintained. The right of belligerency of the state will not be recognized”. Over the years these paragraphs have been subject to interpretation and the Japanese government is talking about changing Article 9.