Soviet republic (system of government) in the context of "Treaty of Creation of the Soviet Union"

In the Soviet Union, a Union Republic (Russian: Сою́зная Респу́блика, romanized: Soyúznaya Respúblika) or unofficially a Republic of the USSR was a constituent federated political entity with a system of government called a Soviet republic, which was officially defined in the 1977 constitution as "a sovereign Soviet socialist state which has united with the other Soviet republics to form the Union of Soviet Socialist Republics" and whose sovereignty is limited by membership in the Union. As a result of its status as a sovereign state, the Union Republic de jure had the right to enter into relations with foreign states, conclude treaties with them and exchange diplomatic and consular representatives and participate in the activities of international organizations (including membership in international organizations). The Union Republics were perceived as national-based administrative units of the Union of Soviet Socialist Republics (USSR).

The Soviet Union was formed in 1922 by a treaty between the Soviet republics of Byelorussia, Russian SFSR (RSFSR), Transcaucasian Federation, and Ukraine, by which they became its constituent republics of the Union of Soviet Socialist Republics (Soviet Union). For most of its history, the USSR was a one-party state led by the Communist Party of the Soviet Union. Key functions of the USSR were highly centralized in Moscow until its final years, despite its nominal structure as a federation of republics; the light decentralization reforms during the era of perestroika (reconstruction) and glasnost (voice-ness, as in freedom of speech) conducted by Mikhail Gorbachev as part of the Helsinki Accords are cited as one of the factors which led to the dissolution of the USSR in 1991 as a result of the Cold War and the creation of the Commonwealth of Independent States.

The Declaration and Treaty on the Formation of the Union of Soviet Socialist Republics (Russian: Декларация и договор об образовании Союза Советских Социалистических Республик) officially created the Union of Soviet Socialist Republics (USSR), commonly known as the Soviet Union. It de jure legalised a political union of several Soviet republics that had existed since 1919 and created a new federal government whose key functions were centralised in Moscow. Its legislative branch consisted of the Congress of Soviets of the Soviet Union and the Central Executive Committee of the Soviet Union (TsIK), while the Council of People's Commissars composed the executive.

The Treaty, along with the Declaration of the Creation of the USSR was approved on 30 December 1922 by a conference of delegations from the Russian SFSR, the Transcaucasian SFSR, the Ukrainian SSR and the Byelorussian SSR. The Treaty and the Declaration were confirmed by the First All-Union Congress of Soviets and signed by heads of delegations – Mikhail Kalinin, Mikhail Tskhakaya, and Grigory Petrovsky, Alexander Chervyakov respectively on December 30, 1922. The treaty provided flexibility to admit new members. Therefore, by 1940 the Soviet Union grew from the founding four (or six, depending on whether 1922 or 1940 definitions are applied) republics to 16 republics.

The Constitution of the Russian Federation (Russian: Конституция Российской Федерации, romanized: Konstitutsiya Rossiyskoy Federatsii) was adopted by national referendum on 12 December 1993 and enacted on 25 December 1993. The latest significant reform occurred in 2020, marked by extensive amendments that altered various sections, including presidential terms, social policies, and the role of Russian law over international ones. (See 2020 amendments to the Constitution of Russia).

Russia's constitution came into force on 25 December 1993, at the moment of its official publication, and abolished the Soviet system of government. The 1993 Constitution is one of the longest-standing constitutions in Russian history, second only to the Soviet Union’s 1936 Constitution, which was in effect until 1977.