It was some months after the war, and the formal dissolution of the State Defence Committee (GKO) on 4 September 1945, when the Politburo began to resume peacetime operations. Formally the Politburo continued in much the same vein as it had left off before the war, with a virtually identical membership and a similarly modest workload. At its meeting of 29 December 1945 the Politburo resolved to meet every other Tuesday for a short time, from 8 pm to 9 pm. . . . Meetings of the Politburo, however, tailed off following the session of 3 October 1946; over the rest of Stalin's reign there were only two further formal, enlarged sessions of the Politburo, on 13 December 1947 and 17 June 1949. The official Politburo in fact came to be overshadowed by the regular conferences of a narrow 'ruling group' which met routinely in Stalin's office. The composition of this circle. . . differed markedly from that of the formal Politburo. Excluded from [it] were those Politburo members who had either fallen foul of Stalin or who were cut off from the ruling circle for reasons of location or ill-health. For some time Stalin's suspicions had fallen on Voroshilov, Andreev, and, to a lesser extent, Kaganovich, all of whom were, despite their formal membership of the Politburo, not privy to the proceedings of the ruling group in the aftermath of the war. . . most resolutions issued in the name of the Politburo in the Stalin years were determined by this group. . . .
A succession of leaders, including Malenkov, Beria, Voznesensky and Bulganin, gained admission to the group many months before their formal accession as full members of the Politburo. Stalin hence unilaterally elevated colleagues without having to go through the tedious formality of having them 'elected' as full members of the Politburo by the Central Committee. Stalin could also expel members from his group with unseemly ease.