WASHINGTON — Though Roland Burris had some trouble being admitted to the U.S. Senate, he will not be easily expelled now that he has arrived.
It takes a vote of two-thirds of the senators to oust a member, and the last senators to be formally expelled were charged with supporting the rebels during the Civil War.
"It's a collegial body that doesn't like to police its members," said Donald A. Ritchie, the Senate's associate historian. "It prefers to leave that to the voters and to the courts."
But a veteran Washington campaign lawyer said that Burris (D-Ill.) may not benefit from the Senate's usual protectiveness toward its members, and that he could face strong pressure from within the Senate to resign.
"He doesn't have a reservoir of goodwill. He is new to the institution, and he arrived under questionable circumstances," attorney Jan W. Baron said.
Burris was appointed in December by then-Illinois Gov. Rod R. Blagojevich to fill President Obama's former seat. Blagojevich made the appointment while facing charges that he had attempted to sell the seat; the Democratic governor has since been impeached and forced out of office. Illinois Republicans and Democrats have pressed for an investigation of Burris as he has changed his characterization of his actions relating to the appointment.
"He has a lot of explaining to do now," Baron said. "If he had testified to all those contacts with people close to Gov. Blagojevich, I don't think he would have been seated.
"They have got to feel snookered, at the very least," Baron said of Senate leaders.
The Senate Ethics Committee has wide powers to investigate members for actions "unbecoming" of a senator. It has been busy over the last two years, and its probes can put political pressure on a senator. Rarely, however, does the committee go much further and impose a public punishment.
"Disciplinary actions by the Senate are few and far between," said Kenneth Gross, a Washington lawyer who specializes in ethics.
For example, after Sen. Larry E. Craig (R-Idaho) pleaded guilty in 2007 to disorderly conduct in an airport men's room, the ethics committee undertook an investigation. Last February, it closed the case by issuing a "public letter of admonition." By then, Craig had announced that he was not seeking reelection.
In May, the committee dismissed a complaint against Sen. David Vitter (R-La.), whose name appeared on a prostitute's client list. The panel noted that Vitter had not been convicted of a crime, and said that the "conduct at issue did not involve use of public office for improper purposes."
It also investigated Sens. Pete V. Domenici (R-N.M.) for calling a U.S. attorney about a pending case involving a Democratic candidate on the eve of an election, and Ted Stevens (R-Alaska), who was convicted on several corruption charges. Domenici retired from the Senate, and Alaska's voters retired Stevens.
Still, the threat of expulsion can pressure embattled senators to resign. In 1995, Sen. Bob Packwood (R-Ore.) was facing expulsion when he resigned after a long investigation into of charges that he had sexually harassed a series of female employees of the Senate.
Sen. Harrison Williams (D-N.J.) was convicted of corruption in the Abscam investigation and resigned in 1982 on the eve of a vote by the full Senate to expel him.
The Senate may impose other public penalties that can ruin a politician's career. In one famous example, Sen. Joseph McCarthy (R-Wis.) was censured by the Senate in 1954, which ended his reign as leader of the anti-communist movement.
Burris' case looks to be unique because he is a newcomer to the Senate, Gross said. "He has been there only for days, and he arrived with two strikes against him," Gross said. "So he's in a weak position to defend himself."
The ethics committee will probably launch an investigation into what Burris said and did before his appointment by Blagojevich. But Gross said the embattled senator would have a chance to answer the charges.
"You have to give him due process," Gross said. "He has a fighting spirit and says he has done nothing wrong. So this could take a while."