Original sentence: In contrast, critics and historians have characterised him as a dictator who oversaw systematic human rights abuses, and whose rule is estimated to have contributed to the deaths of 40–70 million people through starvation, forced labour and executions, ranking his tenure as the top incidence of democide in human history
Edited sentence: In contrast, critics and historians have characterised him as a dictator who oversaw systematic human rights abuses, and claim his rule contributed to the deaths of 40–70 million people through starvation, forced labour and executions, which would rank his tenure as the top incidence of democide in human history, according to their estimations