I’m reading the Stalin and Stalinism (3rd edition) book and it just seems to be the run-of-the-mill dictator stuff. Violence, intimidation, cult of personality, so on. If you want a quote, then there’s page 59-60, here’s a short excerpt (because pasting from a pdf is a removed):

How did Stalin’s state function? The twin pillars of power were the party and the government. The party acted as a parallel government and checked on the implementation of the plans. The flow of information was restricted. The more important an official, the more he was told. The party watched the government, but the political police watched both. Key decision making was centred in Stalin’s own chancellery, presided over by a trusted official, Poskrebyshev. All the threads came together in the chancellery, all the information was pieced together there, the jigsaw was complete. Stalin was the only person in the entire country who saw the whole picture and he skilfully used the information available to him. Stalin’s power was not based on control of the government or the party or the political police. It involved exploiting all three. It was vital to Stalin that he should maintain several independent sources of information; in that way he hoped to judge which source was misleading. After 1936 he successfully prevented any body, be it the Politburo or the CC of the party or the government, meeting as a group and taking counsel together independent of him. He preferred to consult individuals or small groups, and here his tactics were based on setting one person against another. This explains why there were only two Party Congresses between 1934 and 1953, for they were frankly unnecessary. Stalin very seldom left Moscow. He disliked mass meetings and was always con- scious of his Georgian accent. He restricted the number of people who had direct access to him and in so doing created a mystique around his person.

And so on. I haven’t as much time to check out Stalin: Khlevniuk’s book “Stalin: A New Biography of a Dictator” but it seems to have the same opinion and describes the usual features of a dictatorship and Stalin’s role as one. Some short quotes, page 137 onwards:

Would a man living in serious fear of attack venture—let alone relish— such an excursion? The intensification of repression that came in late 1934 was prompted by more complex calculations. Kirov’s murder provided an ideal pretext for action of the sort any dictatorship relies on to promote its central task: solidifying the power of the dictator. Admittedly, by late 1934, Stalin was already a dictator, but dictatorships, like any unstable system of government, depend on the constant crushing of threats. During this period, Stalin faced two such threats, which at first glance appear unrelated. The first was the remnant of the system of “collective leadership” within the Politburo, and the second was the survival of a significant number of former oppositionists. These threats belonged to what might be called Bolshevik tradition. They hung over Stalin like a sword of Damocles, reminders that there were alternatives to sole dictatorship. His fellow Politburo members enjoyed significant administrative, if not political, independence. They ran the various branches of government and had a host of clients from within the party and state apparats. The bonds of institutional and clan loyalties, along with the vestiges of collective leadership and intraparty democracy, were the last impediments to sole and unquestioned power.

Between 1935 and early 1937, the persecution of former oppositionists was accompanied by shake-ups at the highest echelons of power. The Kirov murder strengthened the position of three enterprising young men: Nikolai Yezhov, Andrei Zhdanov, and Nikita Khrushchev. Yezhov’s promotion was especially significant. It was on his shoulders that Stalin placed direct responsibility for conducting the purge. After acquitting himself well in fabricating cases during the Kirov Affair, Yezhov was entrusted with a new assignment—the Kremlin Affair. In early 1935 a group of support staff working in government offices located in the Kremlin—maids, librarians, and members of the Kremlin commandant’s staff—were arrested and accused of plotting against Stalin. Among those arrested were several relatives of Lev Kamenev, who was charged with hatching the plot. 81 The arrestees came under the authority of Stalin’s old friend Avel Yenukidze, who over- saw the running of all Kremlin facilities, and he was accused of abetting the plot. 82 Stalin took a great interest in the Kremlin Affair. The archives show that he regularly received and read arrestee interrogation protocols, made notations on them, and gave specific instructions to the NKVD

This desperate act shows how helpless the Politburo members felt before Stalin, whose control of the secret police made him an indomitable force. The vozhd’s long-standing comrades-in-arms, to say nothing of middle-level functionaries, were a fractured force. They fell all over one another in an effort to ingratiate them- selves with Stalin, each hoping to save his own skin. Such was the state of affairs when the already thinned ranks of the nomenklatura convened for the February–March Central Committee plenum of 1937. During the plenum, Stalin ordered that repression be continued, and Yezhov made a speech calling for a case to be brought against the leaders of the “right deviation,” Nikolai Bukharin and Aleksei Rykov (their fellow “rightist,” Mikhail Tomsky, had already killed himself in August 1936)

Pasting from those books is such a pain that if you want further clarification, I hope you check out the book and maybe in turn point out what you disagree with in their characterization of Stalin as a dictator. To me it seems all very run-of-the-mill description of one.