If we are going just straight off the Warren Commissions report, Oswald assassinated Kennedy for Cold War purposes. He considered himself a Marxist and was constantly trying to get to the Soviet Union. He also considered himself a support of the Cuban Revolution, being on the Fair Play Committee for Cuba. He even tried to get a visa to go to Cuba through the Cuban embassy in Mexico, but the Cuban's denied it, seeing him as being counterproductive. This context is important because the Kennedy president was known for high tensions with the Soviet Union and Cuba. There was the Bay of Pigs and the Cuban Missile Crisis. There was the Cuban Embargo as well as the sabotage campaigns that the American government launched against the Cuban government such as Operation Mongoose.

The tragic irony of this perspective if we take it at face value is that far from helping Cubans and the Soviets it made things worst. Castro in the lead up to the Kennedy assassination was actually negotiating with the Kennedy Administration to normalize relations. Both the Cuban and American ambassadors to the U.N at the time were working on a diplomatic solution and JFK was communicating with Castro indirectly through French reporter Jean Daniel on a way to normalize relations. It was actually in the middle of these negotiations that Castro heard the news of JFK's assassination and was of course as shocked as everyone else.

Now the flip side to all this is that many have questioned the Warren Commission's report both because of the significant among of information that the FBI and CIA left out of their report to the commission, and also due to the fact that the House Committee on Assassinations in 1975 came to the opposite conclusion. They came to the conclusion that there was a second shooter and that the people behind the Kennedy assassination some how had some connection to the Cuban Exile community. So under this scenario assassinating JFK wasn't motivated by support of Fidel Castro but opposition to Fidel Castro, because of JFK's refusal to invade Cuba. Now the House Committee on Assassination's report itself has been questioned and debated as well.