The 44 Dumbest U.S. Presidents Ranked By IQ

5. James Buchanan: 139.6

With an IQ of 139.6, James Buchanan is among the top 5 dumbest American presidents. He briefly attended Dickinson College, but apparently unrelated to his IQ, Buchanan was expelled due to poor behavior. Just barely behind Buchanan, the fourth lowest IQ of any president belongs to…