IMO, the thing that scares the Dems most about this war is the 10,000 plus pages of Iraqi Defense intelligence documents that are still being translated. They are so concerned that if I recall correctly the Dems insisted that these documents be kept out of any new review of the runup to the war. It is not the war that bothers them it is all the other stuff that comes out as a result of fighting. Defund the war and you defund all the other stuff.
I think high profile Dems and their supporters made deals with the devil and will do whatever it takes to make sure these never see the light of day.