Russia, the world's most extensive state, shows a tradition of conveying the weight of its territorial units to foster external policy objectives. The Soviet Union is the only country ever to have subnational entities (the Ukrainian SSR and Byelorussian SSR) recognized as member states in the United Nations, which lasted from 1945 to 1991 (see: Ukraine and the UN). That situation was not to be reflected in constitutional law until the 1977 Soviet Constitution stipulated that a Union republic "has the right to enter into relations with other states, conclude treaties with them, exchange diplomatic and consular representatives, and take part in the work of international organizations" (article 80). The new text went as far as to formally declare that each Union republic "shall retain the right freely to secede from the USSR" (Article 72), which all republics ultimately exercised in 1991.