New poll: more questions than answers

The new NBC/WSJ poll shows Bush hitting a new low (in that poll) of 35% approval. However, this is the second poll in the week showing that in the "generic" Congressional race the Democrats' advantage has slipped markedly, from a 13 percentage point lead in March to a 6 percentage point lead now.

I don't get it. The president is clearly in free fall. Congressional ratings are in free fall. The VP has already hit the ground and gone splat, so he can't fall any further. So, why has the Democrats' lead slipped so much?

Is it because the Dems' leaders continue to show themselves to be spineless?