The author's point is that the Democrats shouldn't wet themselves in excitement over Bush's polling numbers.
If that's the case, then Republicans should also avoid enumerating their fowl prior to their emergence from the shell. After all, the similarities between 1991 and 2003 are striking: popularity following a military campaign in Iraq, a sagging economy, slowly dipping poll numbers.
A more appropriate comparison would be between W and his father. Remember, the elder Bush was still enjoying an approval rating of around 70% in Sept. 1991.