In late 1925, when the 'triumvirate' split into two factions, she openly supported Zinoviev and Kamenev against Stalin, and went into an alliance with Trotsky's Left Opposition in early 1926, to form the United Opposition. Krupskaya was quoted by Trotsky's son Leon Sedov in his book "The Red Book: On the Moscow Trial" as saying "Lenin was only saved from prison by his death". But in a major boost for the leadership, Stalin announced at the end of his speech to the Fifteenth party congress in December 1927 that she had abandoned the opposition.