Bush isn't and never will be a lame duck.
The reason they are voting this way is because they believe WE will vote for them because the Dems are so extreme. The only way to disillusion them of their opinion of US is to take them out in their primaries or on election day if need be.
We are the ones they don't respect.
I do not consider him a lame duck, but, believe me, THEY do think of him that way; all their thinking about now is 2006 and 2008, which, as far as they are concerned, doesn't not involve him.