This question is a little outside of my expertise, but I thought I’d give you an answer since it’s been a couple of days. It’s hard to perfectly answer your question because of its scope. Keep in mind that the Cold War was almost fifty years long. At the same time, there are dozens of nations in Latin America, each with its own political situation, economy, and security concerns that changed over the course of the twentieth century. That being said, here’s a general picture of Soviet involvement in Latin America during the Cold War:

In an effort to stamp out leftist ideologies, the US turned away from its Good Neighbor Policy, the staple of American/Latin American foreign relations in the 1930s, in favor of a more aggressive anti-communist policy. They ratcheted up support for dictators and Latin American militaries. They even directly intervened in Latin American politics. For example, the CIA toppled the Arbenz’s moderately left-leaning government in Guatemala, whose reforms came at the expense of the United Fruit Company. As the Cold War dictated American foreign policy, more and more Latin Americans became disillusioned with these policies, especially because they often ignored the needs of the people. As a result, the United states became an easy scapegoat for persistent inequality found among Latin America’s poor and working classes. Thus, anti-American leftists, communists, and socialists found fertile ground on which to sow their message.

But surprisingly, prior to 1959, the Soviet Union was not involved extensively in Latin America. Early in the Cold War, the USSR lacked the resources to assert itself so far from home, and Stalin remained focused internally during the post war years. Additionally, most in the USSR considered Latin America to be in the United States’s sphere of influence. During the middle and late 1950s, the USSR increasingly looked away from Europe to the third world, but their salvos, according to Bevan Sewell in his article “A Perfect (Free-Market) World? Economics, the Eisenhower Administration, and the Soviet Economic Offensive in Latin America,” were mostly rejected. This view changed after the Cuban Revolution. Fidel Castro looked abroad to bolster its stand against American influence in their economy, and the USSR provided the ultimate counterweight. In a speech given by Khrushchev in July 1960, he states that “for our part, we shall do everything to support Cuba and her courageous people in their struggle for the freedom and national independence which they have won under the the leadership of their national leader Fidel Castro.” The Soviets followed through on this promise. What started as a trade mission turned into the Cuban Missile Crisis, which aside from long range and tactical nukes also included the deployment of thousands of Soviet troops. Following the crisis, the USSR subsequently purchased most of Cuba’s sugar, largely keeping the Cuban economy afloat for much of the twentieth century.

After tasting success in Cuba, Russia turned to new opportunities when they sprang up. The Soviets funneled money to Communist parties in the region. From their embassies, the Soviets could and did participate in espionage activities in various countries. They even brought Latin American students to Soviet universities and exchanged health and agricultural advisors. Also, the Soviet Union engaged in modest trade for natural resources (e.g. Wool from Argentina). However, contrary to American expectations, according to John Charles Chasteen in his book Born in Blood and Fire, “almost never did the Marxists revolutionaries of Latin America organize because of Russian prompting or depend on Russian aid, much less operate on Russian instructions. There simply were no Soviet proxy guerrilla forces in Latin America equivalent to those created by the US government.” The only exceptions were in Central America during the 80s. For example, following the coup against Allende in Chile (who did not receive financial support from the USSR, only political encouragement), communist countries from the Eastern bloc and Cuba sent weapons, military advisors, and humanitarian aid to support the Sandinistas in Nicaragua.

For most of the Cold War, almost all Soviet involvement was directed towards and limited to Cuba. Cuba often used this money to finance revolutions that targeted American interests. For instance, in Latin America, the Cubans supported groups in the Caribbean, Mexico, Guatemala, Venezuela, and Colombia. Cuban revolutionaries were also involved in Indochina and Africa. Yet the distinction must be made between the USSR and the many other left-wing groups that also operated in Latin America during the Cold War. These groups included communists from Eastern-bloc nations, national marxists, maoists, castroists, socialists, populist, and other left-wing groups. Behind each of these groups, the United States saw the USSR, but in reality, very few of them received financial, let alone military support. These groups were independent. Americans with their Cold War blinders on lumped them together, and in the process, completely ignored the political realities that these countries faced.

Thus, Soviet involvement was relatively limited. Marina Oborotova, in her article “Russian Policy In Latin America: Past, Present, and Future”, explains the USSR “never developed a coherent policy toward Latin America...By and large, Soviet policy was either passive or reactive at best. In most important instances, the initiative for Soviet involvement came from the Latin American side, not the other way round. In short, the Soviets were classic opportunists, responding to developments rather than determining them.” The idea that the Soviets lurked behind every anti-American or socialist movement was more a figment of American imagination than a reality. Ironically, the American Cold War policies opened the door to the very forces that they were trying to crush. When the Soviets took advantage of these opportunities, they inadvertently justified American intervention. The force of these interventions exceed what was actually necessary, which in turn, fanned the flames of anti-Americanism and disillusionment. This cycle was only broken by the fall of the Soviet Union.

I hope this overview is helpful. It’s such a long, complex period of time that I had to sweep a lot of the complexity under the rug.