Stalin's rule witnessed violations of human rights on a massive scale. It should be remembered that communist thought generally rejected the idea of natural human rights, primarily because of their solely political nature. But Stalin's violations were not due to any ideological objections to bourgeois political constructs. They were aimed at expanding the power of the Soviet state. To this end, he had rivals murdered on his rise to power, and purged the party to consolidate his gains, having thousands of loyal former Bolsheviks imprisoned or executed without trial. His greatest human rights violations occurred as a result of the collectivization efforts of the early 1930s. Millions of Russian and Ukrainian peasants were forced off of their holdings and onto collective farms. Small landholders, known as kulaks, were essentially liquidated. Moreover, quotas for the collectives were not adjusted for poor harvests, and millions starved to death, both due to famine and deliberate policy on the part of the USSR. Once secure in his power, Stalin created a formidable police state, using secret police to spy on civilians, and imprisoning those accused of dissent. Thousands of intellectuals, artists, and other dissidents were sent to the infamous gulags in Siberia and elsewhere. Overall, Stalin's rule, as his successor Nikita Khrushchev would point out in his so-called "secret speech," was characterized by flagrant violations of human rights.