Of the 12 Democratic senators now on the committee, three will not be back: Russ Feingold (Wis.), who lost on Tuesday; Ted Kaufman (Del.), who was filling a vacancy; and Arlen Specter (Pa.), who lost his party primary. Of the seven Republican members, all are expected to be back.

It might be weeks before Senate leaders determine the new partisan ratio on the committee and how many members it will have. One possible scenario: it stays at 19 members, divided between 10 Democrats and nine Republicans, leaving room for one new Democrat and two new Republicans.