So why are so many Americans convinced, despite all available evidence, that others were involved in the JFK assassination? Much of it has to do with the rapidly declining levels of trust in the American government since the 1960s. While only 52% of Americans believed in a JFK conspiracy theory in 1963 — an idea fostered by legacy media, which claimed that he had been killed by right-wing "hate" — by 1976, that number had skyrocketed to 81%.