How significant were the Purges in the creation of the totalitarian state? (Russia)

The period of the purges (1936-38) involved the widespread surveillance, imprisonment, and execution of ‘counter-revolutionaries’. This was often used as a smokescreen for Stalin to kill his personal political rivals. An example of this was the assassination of Sergei Kirov at the Communist Party headquarters in Leningrad by Leonid Nikolayev. Stalin may have viewed Kirov as a potential rival because of his emerging popularity, and as some historians, notably Conquest, claim there is persuasive evidence for Stalin masterminding his murder to remove the political threat. After the assassination, Nikolayev was immediately arrested and tortured by Yagoda until he signed a statement naming Zinoviev and Kamenev as the leaders of the plot to assassinate Kirov. With this one event, if following on from the view that Conquest holds, Stalin was able to eliminate three of the large competitors in the power struggle, Kirov, Zinoviev, and Kamenev, and discredit their bases by linking the assassin with followers of each in official reports.
In a secret resolution passed by the Politburo, the number of people “to be repressed” was increased by 120,000. The scale of the purges and fear of informants caused so much social instability that it was impossible for any unified challenge to the government due to the complete lack of trust within society. No organisation could be formed because each member would suspect one another of being a spy or informant, and as such the risk was too great for individuals to engage in political opposition to the Bolshevik government. The ability of the purges to completely remove all political and social opposition to the Bolshevik party makes it the most crucial factor in the creation of the totalitarian state. The purges were instrumental in the creation of the totalitarian state, without them Stalin and the Bolshevik party would have been unable to form the block of authority that they did. An opposition, from within or without the party, cannot exist if all your opponents are dead.