My vote has always been for Andrew Jackson, for two reasons. First, he destabilized the financial system, ushering in a century of unnecessary chaos. Second, he mounted a truly evil genocidal campaign against ethnic minorities. To quote Donald Trump (just slightly out of context), “does that sound familiar?”
By the way, I put Truman second for dropping the bomb. Then Lyndon Johnson, for the blood on his hands in Vietnam. I would put George W. Bush in the top 5 or so for starting two aggressive, unnecessary wars and destabilizing an entire region of the globe. If Trump manages to destroy our health care system and set climate change mitigation back by a decade, he may deserve a top 5. If there is a major war or nuclear detonation on his watch, he may still earn that #1 spot.