I have a feeling it was one of those typical "Senate collegiality things" which means the GOP acts like wimps and let Democrats lie and white wash just to maintain the phony veneer of "bipartisanship" in the senate, no matter the cost to truth and the reputation of the president and the case against Saddam. The Senate seems so intent on producing something just for the sake of producing something that they so often go along with the half-assed because standing on principle makes you "too much like the House." Meanwhile, partisan extremists like Levin are allowed to deceive and dissemble all he wants and Senate Republicans just grin and bear it.
They should WANT to look like the house. Senate has about as much cred as the UN.