In Al Franken's 2005 book, "The Truth (With Jokes)", Franken aptly defines the term "cautiously optimistic" with this blurb:
Cautiously optimistic? That's not good. That's an optimist's way of saying, “We're screwed.” I’ve instructed my wife that if a doctor ever tells her that he’s “cautiously optimistic” about my test results, she is to pull the plug immediately. (Source: “The Truth (With Jokes)”, p. 12)
Fast forward to the present. According to the Politico newspaper, Franken is now using that very same phrase to describe his chances in the recount.
Emerging from the meeting with Reid, Franken said that he was "cautiously optimistic" that he would prevail in the recount. (Source: Politico.com, Nov. 19, 2008)