Did citizens of the USSR automatically become citizens of Russia when it switched over?
All persons in the USSR were citizens unless proved to be citizen of a foreign state. [1] This rule avoids statelessness and also subjects every one who cannot prove his foreign citizenship to the strict surveillance to which all citizens are subjected. [1] It also had the effect of broadening the pool of military recruits for conscription. [1] Any person born of a parent who was a citizen of the USSR was also a citizen of the USSR. [1] This practice continued through the later Stalin's 1938 "On USSR Citizenship" law. [1]
All citizens of the USSR were also citizens of an SSR, and all citizens of the SSRs were also citizens of the USSR [3]. The citizenship laws of the SSRs were very similar in form and substance to the USSR citizenship laws [4]. Citizens in the USSR were defined as persons who were citizens of the USSR unless proven otherwise [3]. 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."[1] It also had the effect of building the potential pool of military recruits for conscription [2]. Citizens in the USSR were automatically considered citizens of the Russian SFSR unless explicitly declared otherwise by law [2].