Everyone wants to fight about the smartest president, but honestly the best answer got handed down by another president. In 1962 John F. Kennedy hosted a room full of Nobel Prize winners at the White House and told them, "I think this is the most extraordinary collection of talent, of human knowledge, that has ever been gathered together at the White House, with the possible exception of when Thomas Jefferson dined alone." The whole room laughed because they knew he was barely joking.
Because Jefferson was a genuine freak of nature. He wrote the Declaration of Independence at 33, in about two weeks, and it still reads like scripture. He taught himself to read in something like half a dozen languages. He designed his own home at Monticello and then designed an entire university, buildings, curriculum, and layout, from scratch. He obsessed over science, farming, wine, food, and gadgets, and JFK described him that night as a man who could "calculate an eclipse, survey an estate, tie an artery, plan an edifice, try a cause, break a horse, and dance the minuet."
And here is the part people forget. When the British burned Washington in 1814 and torched the Library of Congress, Jefferson sold the country his personal library to rebuild it, close to 6,500 books covering basically every subject a human being can study. His private collection literally became the foundation of the national library. Who owns 6,500 books in 1815? A maniac. A brilliant one.
Purely on raw wattage, the man was operating on a different frequency than the rest of the list. Two hundred years later we are still living inside sentences he wrote alone at a desk.
Everyone loves to argue about the dumbest president, but the funniest part is that Warren Harding already ended the debate himself. He literally said "I am not fit for this office and should never have been here." Most politicians would rather walk into the sea than admit that. Harding just said it out loud and went back to his card game.
And the record backs him up hard. He stuffed his cabinet with his poker buddies, the so called Ohio Gang, and then let them treat the federal government like their personal piggy bank. His Interior Secretary took cash and cattle to secretly hand off government oil reserves to rich friends. That is the Teapot Dome scandal, and the man actually went to prison for it. His Veterans Bureau chief looted money meant for wounded WWI soldiers. Two of his associates killed themselves as the investigators closed in.
The kicker is that Harding saw it coming. He said his enemies never kept him up at night, it was his friends, because he could not say no to anyone. He even joked it was a good thing he wasn't a woman, because he'd never be able to say no and would always be pregnant. Self awareness was somehow the one thing he had plenty of.
Even his big talent was fake. He gave these grand flowery speeches, and the critic H.L. Mencken said Harding's writing "reminds me of a string of wet sponges, of dogs barking idiotically through endless nights. It is so bad that a sort of grandeur creeps into it." That might be the meanest and most accurate review any president has ever received.
He died in office in 1923 with the scandals still coming apart at the seams, and decades later a DNA test confirmed what people whispered for years, that he'd fathered a child with a much younger woman while he was in the White House.
Historians have parked him at the bottom of the rankings for a hundred straight years. And the wild part is, Harding would probably just shrug and agree with them.