The PoD is simple, a few weeks following Lenin's own death Trotsky trips and falls down a flight of stairs. It wasn't an assassination, guy genuinely died in a random accident.
-Effects on internal Soviet politics in the 1920s and 30s without Trotsky?
-No Trotsky as the most prominent leftist critic of the direction the Soviet Union is heading down under Stalin (or whoever's taking his place if this somehow manages to butterfly Stalin's rise to power). No Trotskyism as an ideology, which no doubt has quite a few impacts on ideological splits many many communist movements worldwide went through.
-Effects on internal Soviet politics in the 1920s and 30s without Trotsky?
-No Trotsky as the most prominent leftist critic of the direction the Soviet Union is heading down under Stalin (or whoever's taking his place if this somehow manages to butterfly Stalin's rise to power). No Trotskyism as an ideology, which no doubt has quite a few impacts on ideological splits many many communist movements worldwide went through.