It's a question asked by a fair few people as the race to the White House heats up and the Trumpster's comments, on everything from immigration to his rival Hillary Clinton, elevate to ever more absurd levels for a Presidential candidate.
Now academics at Oxford University have analysed Trump's tendencies toward the extreme, ranking him on the psychopath scale.
And for anyone decrying demonisation of the Republican candidate - don't worry, they also scored Clinton too.
According to the Psychopathic Personality Inventory (PPI-R), a personality test used by scientists, Trump ranks ahead of Hitler, but behind Saddam Hussein, Henry VIII and Idi Amin.
Meanwhile, Clinton is more of a psychopath than Emperor Nero, Oliver Cromwell and Margaret Thatcher.
The scores for each place both candidates in the population's top 20 per cent for traits associated with psychopaths, which include lack of empathy and fearlessness.
While sharing a ranking with several of the worst people in world history might look bad, don't forget, psychopathic traits are more common among business leaders, surgeons and barristers than in the general population, according to one of the researchers, professor Kevin Dutton.
And we all rank somewhere on the scale.
"The PPI-R does not say that someone is or is not a psychopath," said Dutton, Sky News reports.
"Both great and terrible leaders score higher than the general population for psychopathic traits, but it is the mix of those traits that determines success."
It's essentially just a case of whether those powers are used for good or evil then.
"It is interesting that these scores reflect both the praise and the criticism that Trump and Clinton receive," Dutton continued, ahead of the research paper being published in Scientific American.
"In the end, while both score relatively highly, it will be up to voters to decide if whether their mix of positive and negative traits should send them to the Oval Office or the psychiatrist's office."