Nixon WAS very intelligent, but he always seemed to me to have something missing. Often a very iintelligent person will be a functional idiot because of a rigid commitment to some belief system, but Nixon wasn't an ideologue.

There was something askew in his relationships with other people. He seemed to have a tin ear, as evidenced by his "Checkers" speech. And when it counted, he was a terrible judge of character. His vice presidential pick, Agnew, his closest advisors, Haldeman, Ehrlichman, and Colson, and his attorney general, Mitchell, all did time. Haldeman and Ehrlichman thought it would be a good idea to hire the proven wack-a-doos G Gordon Liddy and E Howard Hunt, respectively. And for what? To subvert the campaign of George McGovern, who would have lost to Ronald McDonald in a fair election.

Nixon was re-elected with, I think, the greatest majority of electoral votes in history, and he managed to kick it all away, his presidency and his legacy, all by himself. There was something in him that subverted all that intelligence and turned him into a sinister doofus.