First of all, the "solid Dem conservatives" are virtually nonexistent. Go to the American Conservative Union's congressional ratings. You have to go to "Louisiana" (on the House Side) to find a Democrat who cracks a "lifetime" fifty percent. Living in the KC area, I'm familiar with two alleged "moderate to conservative" Democrats (Ike Skelton in Missouri, and Dennis Moore in Kansas) who don't hit a fifty percent rating. How is that possible? Because of the very "procedural votes" (and the committee votes) that you mention. The "moderate and conservative" Dems can move a bill to the floor without "officially" voting for it when the bill comes before the entire House for the proverbial "up or down" vote. Only rarely are the "CINO" and "MINO" Dems asked to vote in favor of liberal legislation, and even then only as many votes as may be needed are asked for. Frankly, when you look at the ACU ratings you realize that a "moderate" or "conservative" Democrat is a closeted Liberal.