In December of 1922 the First Congress of People’s Deputies of the USSR approved the Declaration and the Treaty on the Creation of the USSR. The Treaty proclaimed that 4 independent socialist republics: the RSFSR (Russia), the YUSSR (Ukraine), the BSSR (Belorussia) and the ZSFSR (Transcaucasia) with the view of consolidation of the Soviet rule on a voluntary and equal basis were forming a single union state. The Treaty provided for the organization of the all-Union government bodies and defined in general their competence.
On January 31, 1924 the Second Congress of People’s Deputies of the USSR approved the first Constitution of the USSR which became the general law for the single Soviet state.
The 1924 Constitution was fully dedicated to the principles of building the first socialist union multinational state on the basis of the dictatorship of the proletariat. It legally secured the equality of all the USSR nations and their sovereignty. There were approved the National flag, the coat of arms and the capital of the USSR.
The approval and changes to the basic principles of the Constitution were exclusively in the competence of the Congress of People’s Deputies of the USSR. A union republic had the right to withdraw from the Union, its territory could be changed only upon its agreement. The single union citizenship was established. The Union had the exclusive authority for: the external relations and trade; decisions regarding war and peace; organization and management of the armed forces; the general management and planning of the economy and budget; development of the legislation basis (the all-Union justice).
The supreme government body in the USSR was declared the Congress of People’s Deputies of the USSR. In the inter-congress period the role of the supreme government body played the Central Executive Committee of the USSR.
The distinguishing feature of the 1924 main law of the USSR from the following Soviet constitutions consisted in the absence of the state system characteristics, articles on the rights and duties of the citizens, on the suffrage, on local authorities. All these issues were determined by the republic constitutions. The main focus of the 1924 Constitution was the fact of the final legalization of the USSR formation, the rights of the SSR Union and union republics, the system of the supreme government bodies of the SSR Union and union republics.
Source: https://www.prlib.ru/en/history/618994