 In 1925, the 14th Congress of the All-Union Communist Party (Bolsheviks) chose Stalin's policy, defeating Trotsky as a possible leader of the party and of the Soviet Union.In the 1925–1927 period, Stalin dissolved the troika and disowned the centrist Kamenev and Zinoviev for an expedient alliance with the three most right-wing from the Bolshevik period, namely Alexei Rykov (Premier of Russia, 1924–1929; Premier of the Soviet Union, 1924–1930), Nikolai Bukharin and Mikhail Tomsky (leader of the All-Russian Central Council of Trade Unions).In 1927, the party endorsed Stalin's policy of socialism in one country as the Soviet Union's national policy and expelled the leftist Trotsky and the centrists Kamenev and Zinoviev from the Politburo.