Why did Stalin rather than Trotsky emerge as the leader of the USSR after Lenin's death?

'In 1293 Stalin had been on the point of political ruin... six years later he would be in unchallenged power' (Conquest). To see how such a dramatic change, and such an unpredictable defeat of Trotsky, happen you have to look at key figure's personalities, political skill, and or mistakes. You will also have to look at the situation each figure is in, the situation of the country and the political scene in general which is holding …

…d not give the party any clear plan what to do after his death and his criticism of all members meant that no one wanted it read out because it was so damaging to the party. So instead of Stalin being removed from such a high status like Lenin wanted him to be, to prevent a situation like what did occur, he was not and was allowed to take position as head of the USSR.