It went into force globally in 1919, when it was incorporated into the Treaty of Versailles. The primary objective of the convention was to introduce restrictions on exports as opposed to imposing prohibition or criminalising the use and cultivation of opium, coca, and cannabis. That explains the withdrawal of the United States and China, which were gravitating towards prohibitionist approaches, as well as the beginning of negotiations leading to the 1925 International Opium Convention in Geneva.[3]