Of all Nixon's crimes (aside from Vietnam)
Of all Nixon's crimes (aside from things related to Vietnam) the one thing that jumps out at me, for some reason, is trying to plant McGovern campaign literature in Arthur Bremmer's hotel room. (Arthur Bremer is the man who shot George Wallace during the 1972 primaries)
Political use of the IRS is shocking. Talking about bombing the Brookings Institute is shocking. Breaking into Daniel Ellsberg's psychiatrist's office is shocking. Bugging the opposition... it's all shocking.
But the Bremmer thing stands out to me as applying a speciffic CIA-mentality tactic (probably via Howard Hunt) for controlling politics in other nations to our own politics.
Many years later, when Poppy Bush invaded Panama and we were hunting for Noriega the CIA (or military intelligence) hung a photo of Hitler in Noriega's (vacant) bedroom, then let the press in to take pictures.
Don't know just why... but the Bremmer thing stands out. Maybe because it was capitalizing on a political assassination (attempt).
(I wonder if Nixon's people already knew that Nixon had been Bremmer's real target, and he shot Wallace out of mere opportunity.)