I think I read that Nixon, himself had a very high IQ.
He clearly did.
It seemed like he knew a lot about just about everything.
I saw an old interview with Larry King, where King asked questions about geopolitics, the current state of America, economic policy, etc.
Then out of nowhere started asking Nixon about baseball.
Nixon knew the starting lineups of several teams, knew what they were doing, who was "good" and who to watch in the future.
King is a big baseball fan, and seemed taken aback at Nixon's depth of knowledge.
Nixon clearly read just about everything in print, and had a well-informed opinion to share.
Nixon didn't even hem and haw, looking for an answer.
He knew his stuff.