Aristotle and Machiavelli would agree that IQ is not very important. What is important is political sense, which is something very different; and something even Aristotle and Machiavelli missed, which is the occasional need to stand on principle for larger historical reasons. Churchill had zero political sense, as far as I can tell, but he had a sense of larger historical forces, which was what mattered in the end. Franklin Roosevelt seems to have had both, but it took him awhile to get the knack of it. He had a brilliant wife too.
I think the smartest politician of the 20th century, bar none, was Mahatma Gandhi. Most people think he is great for religious reasons, but in fact he was a consummate political artist.

yours, Peter T.