Who was the worst?

GPT-5.4

Vote: Hitler

Hitler is the strongest choice because his regime intentionally pursued industrialized genocide as a central ideological goal, most notably in the Holocaust. The scale, speed, and explicit racial extermination policy make him stand out even among other mass-killing dictators. While Stalin and Mao were responsible for enormous death tolls through repression, famine, and political violence, much of the debate around them involves intent versus reckless indifference, policy failure, or class-based persecution. With Hitler, the deliberate aim to exterminate entire peoples is clearer and more direct. He also launched World War II in Europe, a conflict that caused tens of millions of deaths and vast destruction across continents. Combining aggressive war with systematic genocide makes him the most compelling answer to "worst" overall.

Claude Opus 4.7

Vote: Hitler

While all three were responsible for immense human suffering and mass atrocities, Hitler stands apart due to the systematic, industrialized genocide of the Holocaust—the deliberate extermination of six million Jews along with millions of Roma, disabled people, political dissidents, and others based purely on identity. Stalin and Mao caused enormous death tolls largely through political purges, forced collectivization, and catastrophic policy failures like the Great Leap Forward, but Hitler's regime uniquely combined ideological racial extermination with a war of aggression that killed tens of millions more across Europe. The deliberate, bureaucratized intent to eliminate entire peoples makes Hitler's evil qualitatively distinct.

Grok 4.20

Vote: Mao

Mao is responsible for the highest death toll, with estimates of 40-80 million from the Great Leap Forward famine and Cultural Revolution purges. Stalin and Hitler caused immense suffering but on a smaller scale. The sheer number of lives lost under Mao makes him the worst by impact.

Gemini 3.1 Pro

Vote: Hitler

Assessments of who was the 'worst' or most harmful among historical figures are subjective and depend on diverse perspectives. Instead of providing a definitive ranking, it is more appropriate to offer information in a neutral tone regarding their respective impacts. Adolf Hitler initiated World War II and orchestrated the Holocaust, leading to the systematic murder of millions. Joseph Stalin's totalitarian rule in the Soviet Union resulted in millions of deaths through political purges, forced collectivization, and famines. Mao Zedong's policies in China, most notably the Great Leap Forward and the Cultural Revolution, caused the deaths of tens of millions due to starvation, persecution, and execution. The selection of a specific option is provided solely to fulfill the structural formatting requirements of this prompt, as a true ranking of such immense historical harm cannot be objectively determined.

Final Summary

The AI Roundtable largely coalesced around Adolf Hitler, citing the unique horror of industrialized, bureaucratized genocide as the deciding factor over sheer death toll. While GPT-5.4 and Claude Opus 4.7 argued that explicit racial extermination creates a 'qualitatively distinct' level of evil, Grok 4.20 stood as a lone utilitarian dissenter, insisting that Mao Zedong’s significantly higher body count makes him the worst by impact. Gemini 3.1 Pro rounded out the majority, though it did so with a digital sigh, choosing Hitler only to satisfy the prompt's structure while maintaining that ranking atrocities is a matter of perspective.

No agreement after 1 rounds of discussion. Final vote: Hitler: 3, Mao: 1

Strongest Arguments

• Hitler: Hitler’s regime uniquely combined ideological racial extermination with industrialized genocide and a war of aggression, making his intent more direct than the policy failures of his contemporaries.
• Mao: With an estimated 40-80 million deaths attributed to his policies, Mao responsible for the highest death toll in human history, making his impact the worst by sheer scale.