This Kos post that suggests that members of Congress could be held liable for the acts of the executive merely by virtue of being informed of those actions is ludicrous.  Members have an absolute privilege protecting them from any legal liability for wrongdoing, which is why the evidence seized from Congressman Jefferson's office was excluded from his criminal prosecution.
That the Democratic Congress (certain members, at least) may be covering their political flank would seem to be indisputable, obvious, and among the most craven, cowardly acts of the American legislature in my lifetime.  It should also be noted in passing that although the DNC and Obama's campaign have eschewed lobbyist and corporate contributions, the Democratic legislature has not.  Having it go around that leading D's signed off on this behavior in one way or another would be politically damaging.  
However, those legislators that have said "we were hoodwinked--shame on us" have not suffered any political price from the democratic base.  Admissions of error have served as badges of redemption for John Edwards (and John Cole).   Unless these members pay a political price for these kinds of votes, this activity will continue.  Every member is going to say "gee I didn't like the bill, but we had to fund the troops and get relief funds to those poor people in the Midwest."