Here's a pretty good little piece by Carl Cannon of the National Journal on lame duck through the decades. He writes that the term "lame duck" was first used in 1910, and not to refer to a president, but to Republicans who hadn't survived the midterm elections but still had several months to serve before their replacements took over.
I've been calling GWB a lame duck for almost three years now, though some didn't start using the term until after he gave up on Social Security reform, some sfter the Democrats won Congress in 2006, and some not until the latest version of an immigration bill failed. The important thing to remember -- the VIPS group I mentioned in a previous post certainly do -- is that whatever the status of his popularity or his support in Congress, a sitting president still has a great deal of power. He still has veto power, he can still promulgate executive orders and signing statements, and he is still commander-in-chief of the military.
One of the odd things about Bush is that he seems to live in a bubble more than most presidents, so there's no knowing just how much he lets his current weakened condition seep into his own consciousness. But there's a serious question whether a wounded Bush is more dangerous than a Bush with reason to feel confident.