Answer
Rákosi's downfall can be attributed to the "Secret Speech" delivered by Nikita Khrushchev, the First Secretary of the Communist Party of the Soviet Union, in 1956. Khrushchev's speech denounced the oppressive policies and personality cult of Joseph Stalin, Rákosi's mentor and ally. The revelations contained in the speech sparked widespread political unrest and dissent within Hungary and led to Rákosi's eventual demotion and removal from power.