Soviet involvement in regime change

Soviet involvement in regime change entailed both overt and covert actions aimed at altering, replacing, or preserving foreign governments. In the 1920s, the nascent Soviet Union intervened in multiple governments primarily in Asia, acquiring the territory of Tuva and making Mongolia into a satellite state. During World War II, the Soviet Union helped overthrow many puppet regimes of Nazi Germany and the Empire of Japan, including in East Asia and much of Europe. Soviet forces were also instrumental in ending the rule of Adolf Hitler over Germany.
In the aftermath of World War II, the Soviet government struggled with the United States for global leadership and influence within the context of the Cold War. It expanded the geographic scope of its actions beyond its traditional area of operations. In addition, the Soviet Union and Russia engaged in foreign electoral intervention in the national elections of many countries. One study indicated that the Soviet Union and Russia engaged in 36 interventions in foreign elections from 1946 to 2000.
The Soviet Union ratified the UN Charter in 1945, the preeminent international law document, which legally bound the Soviet government to the Charter's provisions, including Article 2, which prohibits the threat or use of force in international relations, except in very limited circumstances. Therefore, any legal claim advanced to justify regime change by a foreign power carries a particularly heavy burden.
The U.S. government examined cases of Soviet interventions within the context of international law, specifically the interpretation of the UN Charter in view of sovereignty and the use of force. Some cases have been discussed in official U.S. documentation.

1921–1940: Interwar period

1920s

1921–1924: Mongolia

The Mongolian Revolution of 1911 saw Mongolia declare independence from the Qing dynasty in China, ruled by Bogd Khan. In 1912, the Qing dynasty collapsed into the Republic of China. In 1915, Russia and China signed the Kyatha agreement, making it autonomous. However, when the Russian Civil War broke out, China, working with Mongolian aristocrats, retook Mongolia in 1919. At the same time the Russian Civil War raged on and the White Army were, by 1921, beginning to lose to the Red Army. One of the commanders, Roman Ungern Von Sternberg, saw this and decided to abandon the White Army with his forces. He led his army into Mongolia in 1920, and conquered it completely by February 1921, putting Bogd Khan back into power.
The Bolsheviks had been worried about Sternberg and, at the request of the Mongolian People's Party, invaded Mongolia in August 1921 helping with the Mongolian Revolution of 1921. The Soviets moved from many directions and captured many locations in the country. Sternberg fought back and marched into the USSR but he was captured and killed by the Soviets on 15 September 1921. The Soviets kept Bogd Khan in power, as a constitutional monarch, hoping to keep good relations with China, while continuing to occupy the country. However, when Bogd Khan died in 1924, the Mongolian Revolutionary government declared that no reincarnations shall be accepted and set up the People's Republic of Mongolia which would exist in power until 1992.

1929: Tannu Tuva

After the fall of the Qing Dynasty in the 1911 Revolution, the province of Tannu Uriankhai became independent, and was then made a protectorate of the Russian empire. During the Russian Civil War, the Red Army created the Tuvan People's Republic. It was located in between Mongolia and the USSR and was only recognized by the two countries. Their Prime Minister was Donduk Kuular, a former Lama with many ties to the Lamas present in the country. He tried to put his country on a Theocratic and Nationalistic path, tried to sow closer ties with Mongolia, and made Buddhism the state religion. He was also resistant to the collectivization policies of the Soviet Union. This was alarming and irritating to Joseph Stalin, the Soviet Union's leader.
The Soviet Union would set the ground for a coup. They encouraged the "Revolutionary Union of Youth" movement, and educated many of them at Communist University of the Toilers of the East. In January 1929, five youths educated at the school would launch a coup with Soviet support and depose Kuular, imprisoning and later executing him. Salchak Toka would become the new head of the country. Under the new government, collectivization policies were implemented. A purge was launched in the country against aristocrats, Buddhists, intellectuals, and other political dissidents, which would also see the destruction of many monasteries.

1929: Afghanistan

After the Third Anglo-Afghan War, the Kingdom of Afghanistan had full independence from the British Empire, and could make their own foreign relations. Amanullah Khan, the king of Afghanistan, made relations with the USSR, among many other countries, such as signing an agreement of neutrality. There had also been another treaty signed that gave territory to Afghanistan on the condition that they stop Basmachi raids into the USSR. As his reign continued, Amanullah Khan became less popular, and in November 1928 rebels rose up in the east of the country. The Saqqawists allowed Basmachi rebels from the Soviet Union to operate inside the country after coming to power. The Soviet Union sent 1,000 troops into Afghanistan to support Amanullah Khan. When Amanullah fled the country, the Red Army withdrew from Afghanistan. Despite the Soviet withdrawal, the Saqqawists would be defeated later, in 1929.

1930s

1933–1934: Xinjiang

In 1934, Ma Zhongying's troops, supported by the Kuomintang government of the Republic of China, were on the verge of defeating the Soviet client Sheng Shicai during the Battle of Ürümqi in the Kumul Rebellion. As a Hui, he had earlier attended the Whampoa Military Academy in Nanjing in 1929, when it was run by Chiang Kai-shek, who was also the head of the Kuomintang and leader of China.^{Soviet invasion of Xinjiang#cite note-4| Soviet invasion of Xinjiang#cite note-5|} He was then sent back to Gansu after graduating from the academy and fought in the Kumul Rebellion where, with the tacit support of the Kuomintang government of China, he tried to overthrow the pro-Soviet provincial government first led by Governor Jin Shuren, and then Sheng Shicai. Ma invaded Xinjiang in support of Kumul Khanate loyalists and received official approval and designation from the Kuomintang as the 36th Division.
In late 1933, the Han Chinese provincial commander General Zhang Peiyuan and his army defected from the provincial government side to Zhongying's side and joined him in waging war against Jin Shuren's provincial government.
In 1934, two brigades of about 7,000 Soviet GPU troops, backed by tanks, airplanes and artillery with mustard gas, crossed the border to assist Sheng Shicai in gaining control of Xinjiang. The brigades were named "Altayiiskii" and "Tarbakhataiskii".^{Soviet invasion of Xinjiang#cite note-6|} Sheng's Manchurian army was being severely beaten by an alliance of the Han Chinese army led by general Zhang Peiyuan, and the 36th Division led by Zhongying,^{Soviet invasion of Xinjiang#cite note-7|} who fought under the banner of the Kuomintang Republic of China government. The joint Soviet-White Russian force was called "The Altai Volunteers". Soviet soldiers disguised themselves in uniforms lacking markings, and were dispersed among the White Russians.^{Soviet invasion of Xinjiang#cite note-8|}
Despite his early successes, Zhang's forces were overrun at Kulja and Chuguchak, and he committed suicide after the battle at Muzart Pass to avoid capture.
Even though the Soviets were superior to the 36th Division in both manpower and technology, they were held off for weeks and took severe casualties. The 36th Division managed to halt the Soviet forces from supplying Sheng with military equipment. Chinese Muslim troops led by Ma Shih-ming held off the superior Red Army forces armed with machine guns, tanks, and planes for about 30 days.^{Soviet invasion of Xinjiang#cite note-9|}
When reports that the National Revolutionary Army had defeated and killed the Soviets reached Chinese prisoners in Ürümqi, they were reportedly so jubilant that they jumped around in their cells.^{Soviet invasion of Xinjiang#cite note-10|}
Ma Hushan, Deputy Divisional Commander of the 36th Division, became well known for victories over Russian forces during the invasion.^{Soviet invasion of Xinjiang#cite note-11|}
Chiang Kai-shek was ready to send Huang Shaohong and his expeditionary force which he assembled to assist Zhongying against Sheng, but when Chiang heard about the Soviet invasion, he decided to withdraw to avoid an international incident if his troops directly engaged the Soviets.^{Soviet invasion of Xinjiang#cite note-12|}

1936–1939: Spain

The newly created Second Spanish Republic became tense with political divisions between right- and left-wing politics. The 1936 Spanish general election would see the left wing coalition, called the Popular Front, win a narrow majority. As a result, the right wing, known as Falange, launched a coup against the Republic, and while they would take much territory, they would fail at taking over Spain completely, beginning the Spanish Civil War. There were two factions in the war: the right wing Nationalists, which included the Fascist Falange, Monarchists, Traditionalists, Carlists, wealthy landowners, and Conservatives, who would eventually come to be led by Francisco Franco, and the left wing Republicans, which included Anarchists, Socialists, Basque separatists, Catalan separatists, Liberals, and Communists.
The Civil War would gain much international attention and both sides would gain foreign support through both volunteers and direct involvement. Both Nazi Germany and Fascist Italy gave overt support to the Nationalists. At the time, the USSR had an official policy of non-intervention, but wanted to counter Germany and Italy. Stalin worked around the League of Nations's embargo and provided arms to the Republicans and, unlike Germany and Italy, did this covertly. Arms shipment was usually slow and ineffective and many weapons were lost, but the Soviets would end up evading detection of the Nationalists by using false flags. Despite Stalin's interest in aiding the Republicans, the quality of arms was inconsistent. Many rifles and field guns provided were old, obsolete or otherwise of limited use, but the T-26 and BT-5 tanks were modern and effective in combat. The Soviet Union supplied aircraft that were in current service with their own forces but the aircraft provided by Germany to the Spanish Nationalist Air Force proved superior by the end of the war. The USSR sent 2,000–3,000 military advisers to Spain, and while the Soviet commitment of troops was fewer than 500 men at a time, Soviet volunteers often operated Soviet-made tanks and aircraft, particularly at the beginning of the war. The Republic paid for Soviet arms with official Bank of Spain gold reserves, 176 tonnes of which was transferred through France and 510 directly to Russia which was called Moscow gold. At the same time, the Soviet Union directed Communist parties around the world to organize and recruit the International Brigades.
At the same time, Stalin tried to take power within the Republicans. There were many anti-Stalin and anti-Soviet factions in the Republicans, such as Anarchists and Trotyskyists. Stalin encouraged NKVD activity inside of the Republicans and Spain.
Catalan Trotskyist Andreu Nin, socialist journalist Mark Rein, left-wing academic José Robles, and others were assassinated in operations in Spain led by many spies and Stalinists such as Vittorio Vidali, Iosif Grigulevich, Mikhail Koltsov and, most prominently, Aleksandr Mikhailovich Orlov, who later defected to the United States. The NKVD also targeted Nationalists and others they saw as politically problematic to their goals.
The Republicans eventually broke out into infighting between the communists and anarchists, as both groups attempted to form their own governments. The Nationalists, on the other hand, were much more unified than the Republicans, and Franco had been able to take most of Spain's territory, including Catalonia, an important area of left wing support and, with the collapse of Madrid, the war was over with a Nationalist victory.