I kind of figured that the claim McBush would only seek one term was an urban legend. There is something to it. From the January 3, 2008 Boston Globe

Like I said earlier, what's the incentive to vote for a president who will only have the chance to implement policy for 2 to 2.5 years? The next set of candidates will be taking away the spotlight and, more importantly, Congress can stall on anything they want for the next president.