If Sen. Ted Stevens is found guilty and re-elected, it will be up to the Senate to decide whether he can keep his seat or should be expelled.
It's never happened before. Four senators in U.S. history have been convicted of crimes, but two resigned, one died and one saw his term expire before an expulsion vote took place. Two-thirds of the Senate would have to vote to expel.
"The Senate is a very collegial body and really doesn't like to act in that sense," Don Ritchie, an associate Senate historian, said in an interview Wednesday. He said the Senate would be likely to wait for any appeals to be settled before taking action.
The last actual expulsion of a senator occurred during the Civil War. Sen. Jesse Bright, D-Indiana, was kicked out for writing a letter to Jefferson Davis, president of the Confederate states, recommending a friend's gun manufacturing business in Texas.
Bright's letter was written a month before the Confederacy shelled Fort Sumter to start the war. He was expelled in early 1862.
Stevens is the 11th senator to be indicted for a crime. In September, on a visit to Anchorage, he said he would not consider stepping down or quitting his campaign for re-election because he expects to win his legal case.
"Put this down: That will never happen -- ever, OK?" Stevens said. "I am going to run through and I am going win this election."
The Constitution leaves it up to the Senate to decide who can serve. Senators do not like to step forward until after the voters and the judicial branch have spoken, Ritchie said.
Nine senators in U.S. history have been subjected to a lesser rebuke known as censure, which does not cost them their seats.
The most recent senatorial expulsion case involved ethics charges but no criminal indictment. Oregon Republican Bob Packwood resigned in 1995 after the Senate Ethics Committee recommended expulsion based on multiple accusations of sexual harassment.
In 1990, Sen. David Durenberger, R-Minn., was denounced by the Senate for circumventing rules about outside income, and he spent the last two years of a 17-year career under indictment for misusing public funds. He did not run for another term in 1994, and eight months after leaving the Senate he pleaded guilty to a misdemeanor, for which he was fined and sentenced to probation.
One senator pushed it to the brink. In 1981, Sen. Harrison Williams, D-NJ, was convicted of accepting bribes from a fake business in the FBI's Abscam investigation. That FBI sting also resulted in convictions of five members of the House of Representatives.
Williams continued serving as he appealed, arguing unsuccessfully that he'd been entrapped. After an expulsion debate on the Senate floor in 1982, Williams resigned before a vote could be taken.
The two other senators convicted of crimes while in office were Sen. Joseph Burton, R-Kansas, who resigned in 1906, and Sen. John Mitchell, R-Oregon, who died in office in 1905 while his case was on appeal.
Sen. Kay Bailey Hutchison, R-Texas, who came to Anchorage this week to campaign for Stevens, was indicted in Texas shortly after her election in 1993 on charges that she had used her office as state treasurer to campaign for the Senate. The charges were eventually dropped.
No senator convicted of a crime has ever received a presidential pardon. Williams sought a pardon from President Bill Clinton but was turned down.