The Domino Theory became an important part of American foreign policy during the Cold War. It states that once one country falls under the influence of communism, there is a heightened chance that its neighboring countries will also succumb. It was the main motivation behind several of the United States' conflicts in the twentieth century such as the Korean War and the Vietnam War.

Karl Marx, writer of The Communist Manifesto, expected the communist revolution to take place first in Britain, Germany, or the United States. That it should happen first in Russia, a comparably undeveloped country, would have been a massive surprise to Marx. 

In the aftermath of World War II, the allied powers and several other democratic nations formed NATO, an agreement to provide for the cooperative growth of capitalist societies and to counter the rising threat of Soviet influence. The Warsaw Pact was formed shortly after as a countermeasure. It incorporated all the communist nations of Eastern Europe into a treaty with the Soviet Union.

During the 1980s, the Soviet Union underwent a revolution of sorts that paved the way for the fall of communism just a few years later. This revolution is generally referred to as "glasnost" and "perestroika." "Perestroika" was the restructuring of the political system. "Glasnost" was the opening of freedoms of speech and the press in Russian society.

The Russian Revolution took place in 1917 during World War I. The tsar at the time, Nicholas II, was overthrown, and his government was replaced with a communist government that would grow into the USSR. When the Russian Revolution took place, the population was decimated from warfare and famine, and the new communist government pulled Russia out of the First World War.

The Bolsheviks and Mensheviks were the two primary socialist political parties in 1917, the time of the revolution in Russia. The Mensheviks were lead by Alexander Kerenskii and the Bolsheviks were lead by Lenin. The Bolsheviks were the majority and differed from the Menshevik minority in their beliefs; Mensheviks favored a gradual change and opposed revolution, and the Bolsheviks desired absolute control for the Socialist Party and favored revolution as opposed to gradual change. The Bolsheviks and Lenin would emerge in control.

The Great Purge was a campaign initiated by Stalin in 1934 to remove all “undesirable” elements from the Communist Party and the Soviet Union. In practical terms, it involved the removal of numerous government officials from their positions, the execution of much of the Red Army’s leadership, repression of the peasantry, and the execution and imprisonment of intellectuals. The Purge was primarily caused by Stalin’s desire to consolidate his control over the Communist Party and to remove any factions who might remain loyal to his chief challenger, Leon Trotsky.

When Russian President Mikhail Gorbachev rose to power in 1985 he set about reviving the stagnant Russian economy. He soon realized that the Soviet Union’s extensive economic problems could not be resolved without a complete restructuring of the political and social institutions of the U.S.S.R. To this end he adopted two famous policies called “glasnost” (openness) and “perestroika” (restructuring). “Perestroika” sought to replace Russia’s planned economy with something much more akin to a western economic system, whereas “glasnost” was designed to implement openness and accountability into the Soviet government. These two major reforms are usually credited with bringing about the end of communism and fracturing the Soviet Union. 

“Glasnost” was a policy of openness implemented by Russian President Mikhail Gorbachev in the waning years of the Soviet Union. Its primary intention was to provide the public with greater access to information and ensure higher levels of accountability in the government.

The Russian Revolution of 1917 is the collective term given to the process whereby the Tsarist regime was overthrown and replaced by the Soviet Union. Due to differences at the time between the European and Russian calendars, the two revolutions are called either “the February and October Revolutions” or “the March and November Revolutions.” The March revolution overthrew the Tsarist regime and replaced it with a provisional government; however, the Socialists were still not in complete control, and in November, Lenin overthrew the provisional government and established the Soviet Union.