Kevin Gunn spent several years as Dick Gephardt's chief of staff. He was running for the senate seat currently held by the Senate pro-team, St. Louis County's Michael Gibbons.

Gunn's sudden withdrawal from the race, however, brought some criticism from members of his own party. 

Democratic Senator Victor Callahan said he's not pleased with Gunn's decision to accept the nomination while still raising money for an active campaign.

Callahan's filibuster stalled Senate action.  It was the Senate's president Pro Tem, Mike Gibbons, a Republican, who sponsored Gunn's appointment.

Republicans say Democrats are bent out of shape because they lost a promising candidate for an important Senate seat.

Reporting from the state capital, I'm Jennifer Moore.