The strong possibility Donald Trump might actually be the Republican nominee for president has left many conservatives distraught and driven one adviser to Marco Rubio to publicly declare he prefers the Soviet dictator Josef Stalin over the flamboyant billionaire.

Max Boot, a Council on Foreign Relations fellow and foreign policy adviser to the Florida senator, told The New York Times “I would sooner vote for Josef Stalin than Donald Trump” for a Thursday article covering how some conservatives will never cast their ballot for Trump.

“There is no way in hell I would vote for him. I would far more readily support Hillary Clinton,” Boot added.

Stalin is responsible for the deaths of at least 20 million non-combatants and instigated such atrocities as the forced famine of Ukraine in the 1930s. It is unclear what crimes against humanity Boot thinks a President Trump would unleash that could match the Soviet premier’s brutal reign.

The CFR scholar and noted neoconservative also told Vox on Tuesday “I’m literally losing sleep over Donald Trump.”

Boot said to Vox he hates Trump because he finds the businessman to be a “fascist demagogue,” “bigoted and ignorant,” and espouses a “crackpot” foreign policy. He hopes that if Trump gets the GOP nomination, the party will fracture soon after.

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