Soviet nationality and citizenship law controlled who was considered a citizen of the Union of Soviet Socialist Republics, and by extension, each of the Republics of the Soviet Union, during that country's existence. The nationality laws were only in rough form from about 1913 to 1923, taking more definite form in 1924. There were several major changes in the nationality law, especially in 1931, 1938, and 1978. Soviet law originally expanded the bounds of jus sanguinis and citizenship by residence more than was common among European countries, before tending to gradually retract from that over time. Soviet citizenship law was also used as a political tool to expand the number of Soviet citizens globally, increase military conscription pools, and punish dissenters or even entire ethnic grou