Original sentence: He was directly and indirectly responsible, via his policies, for tens of millions of deaths and unjust deportations to labour camps in the Soviet Union.Stalin's cult of personality, his extreme concentration of power and the means of its execution characterized his rule
Edited sentence: He was directly or indirectly responsible, certain historians allege, via his policies, for tens of millions of deaths and unjust deportations to labour camps in the Soviet Union.Stalin's cult of personality, his extreme concentration of power and the means of its execution have led some to define him as a dictator