[Ol' Dan Tucker]

a Clinton Administration Holdover?

Hardly. More like a GHW Bush holdover.

Wilson was undersecretary to Ambassador April Glaspie in Iraq in 1990. (Meeting Saddam Diplomat Joe Wilson Recalls Meeting With the Iraqi Leader) This is only one of hundreds of links available through Google.

[Miss Marple]

Well, actually, if you wish to be technically correct, he was a CARTER holdover. He first went to work for the State Department in 1976 as a career diplomat.

His full biography may be read here. By the way, this is the biography that gives his wife's maiden name.