James Buchanan – IQ 139.6

Honestly, it is surprising that James Buchanan’s IQ score stands only at 139.6! The 17th President of the USA was a polymath who served as a private in the military, a lawyer registered with the Pennsylvania Bar Association, and a Secretary of State.

In his lifetime, Buchanan had predicted that history would vindicate his actions, and that proved to be true to a certain extent. While the man had a tough time in the office, historians suggest that he could have done much better had it been a different era.