CNN reports that Senate Democrats plan to block Roland Burris, Blagojevich's appointee to Obama's vacated Senate seat, from entering the Senate floor:
The aide familiar with Senate Democratic leaders' plans said if Burris tries to enter the Senate chamber, the Senate doorkeeper will stop Burris. If Burris were to persist, either trying to force his way onto the Senate floor or refusing to leave and causing a scene, U.S. Capitol Police would stop him, said the aide.
What right do Harry Reid and the rest of the Senate Democrats have to keep Burris from entering the Senate floor? The Constitution gives the Senate, not Reid or the Democrats, the right to determine its members. Until the 111th Congress formally meets, and until the Senate formally votes to deny Burris his seat in the Senate, Burris has as much right to enter the Senate floor as any other new member of the Senate.
It is an abuse of his power for Reid to use the Senate doorkeeper or the U.S. Capitol Police against Burris until a vote by the full Senate is taken to deny Burris his lawfully appointed seat.
EDIT (1/4/09): Reid and the Senate Democrats have softened their stance a little. It appears that if he has a valid certicate of appointment, he will be allowed on the Senate floor. This new stance seems valid to me. According to Fox news:
The certificate of appointment must bare the signatures of both the governor and the secretary of state. Secretary of State Jesse White who has refused to sign the document because of the allegations of corruption against the governor.
Should the Illinois Supreme Court force White to sign the document, a move Burris is seeking, Burris would be allowed on the Senate floor. Reid or some other Democrat would then have to object to Burris being seated and call up a resolution that would send his credentials to the Rules Committee pending an investigation.
EDIT (1/5/09): The Wall Street Journal published an editorial 1/3/09 stating that according to the Supreme Court's opinion in Powell v. McCormack (1969), the Senate must seat Burris but can then expel him with a 2/3 rds vote.
Assuming that Burris obtains certification by the Illinois secretary of state (which is a nodiscretionary duty and will probably be compelled by the Illinois state courts), the Senate must seat him and can then expel him if they wish.