Only Nixon could go to China

[Jeffrey William McKeough]

I just heard the phrase "Only Nixon could go to China" attributed to
Mr. Spock in Star Trek 6 for the millionth time.  (When Captain Kirk
asks Spock why Kirk was chosen to be the envoy to the Klingons, who
killed his son, Spock says this to him and claims that it's an ancient
Vulcan saying.)

I once did some research on the saying and I found a bunch of
references over the years, but I couldn't find out who first said it.
Does anyone know?

--
Jeffrey William McKeough
jwm at spdcc.com (or spdcc.net)