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 groups.
After the Russian Revolution, between 1917 and 1923, citizenship and nationality questions were subject to the control of various bodies in the "numerous independent and semi-independent republics and regions."
Earlier leaders did not focus on nationality law, because they believes that an ongoing worldwide Communist revolution would eventually join all person on the world into one larger Communist citizenship.
The 1918 constitution of the Russian SFSR did not draw a clear distinction between citizens and non-citizens, instead simply extending rights of Russian citizens to non-citizens within the Russian Republic.
While residents of the Russian Empire were initially welcomed by the government to return, after the Russian Civil War, the Bolshevik party leadership engaged in mass denaturalization of Russians who had left.
The 1923 USSR constitution established a single uniform USSR citizenship for all citizens of the SSRs.
It was not until October 29, 1924 that the first comprehensive citizenship law or regulations came into effect in the USSR, making it difficult to determine citizenship status until then.
The first comprehensive Soviet law on citizenship, in 1924, established USSR citizenship, status of foreigners, citizenship at birth, citizenship effect on children of their parents, and naturalization. A 1930 revision modified a few details. It also greatly expanded the power to denaturalize citizens.
All citizens of the USSR were also citizens of an SSR, and all citizens of the SSRs were also citizens of the USSR. The citizenship laws of the SSRs were very similar in form and substance to the USSR citizenship laws.
Citizenship in the individual SSRs "formally existed but had no practical or political consquences" because it was subsumed into USSR citizenship. Experts believes that SSR citizenship was largely non-existent.
All persons in the USSR were citizens unless proved to be citizen of a foreign state. The rule avoids statelessness, and also "subject[s] every one who cannot prove his foreign citizenship to the strict surveillance to which all citizens are subjected." It also had the effect of building the potential pool of military recruits for conscription.
Any person born of a parent who was a citizen of the USSR was also a citizen of the USSR, which extended the principle of the previous imperial regime. This practice continued through the later Stalin's 1938 "On USSR Citizenship" law, in order to broaden the number of Soviet citizens.
Marriage to a USSR citizen did not automatically confer citizenship, which was seen as a break from European bourgeois customs. The citizenship of a child under 14 generally changes with the citizenship of the parents, either to or away from USSR citizenship, but did not do so automatically if the parents' citizenships differed, which was also seen as a break from European custom.
It was originally designed to replace all earlier Soviet citizenship regulations and laws, until that provision was removed, as it was too terse to provide substantial guidance, so that only conflicting earlier provisions were replaced. The 1938 law no longer stated that all persons in Soviet territory were presumed to be citizens. It created officially stateless persons who did not have Soviet citizenship and could not prove other citizenship. The 1931 act was repealed in 1939.
Details of naturalization in the 1931 law were deliberately kept vague, so as to provide full power to administrative authorizes to decide upon who might be admitted to citizenship.
In general, Soviet citizenship law was very inclusive in theory.
There were no official requirements for residency; knowledge of language, history, constitution, or political system; minimum income; or the like. All that was required was an application and renunciation of other citizenships, and specifying of a particular SSR citizenship.
In the period leading up to the 1938 law, the Soviet political system made strong use of deprivation of citizenship and reinstatement as instrument of discipline and sanction. Entire groups or categories were stripped of citizenship or the rights of citizenship.
In the 1940s a variety of decrees concerning USSR citizenship for persons from specific areas and regions were enacted, including:
In February 1947, the USSR prohibited marriage between citizens of the USSR and aliens, but repealed that law in November 1953. In March 1948, the USSR laid out procedures for Lithuanian, Latvian, and Estonian nationals living in Latin America to acquire Soviet citizenship.
A 1954 citizenship decree that reinstated the 1931 citizenship regulations changed the outlines of who was a Soviet citizen by stating that all persons who have "long resided" in Soviet territory were Soviet citizens, including those persons who had been denied citizenship.
Changes to the USSR's citizenship laws were also enacted by 1977 constitution and the December 1, 1978 law on citizenship.