Can Roy Moore be expelled if he wins Alabama's Senate seat?

While calls for Roy Moore to step down have grown louder after a fifth woman accused him of sexual misconduct on Monday, the Senate hopeful shows no signs of conceding.

Despite polls that show his cushy lead over Democrat Doug Jones has all but vanished with one month left until the Alabama special elections, 50 pastors showed their steadfast support for Moore in a letter that claimed he would “fight for morality.”

And even if Moore steps down, it’s too late for his name to be removed from the ballot under state rules.

Sen. Cory Gardner (R-CO) certainly accounted for the possibility that Moore could go on to win the seat in Alabama, a state that hasn’t elected a Democratic U.S. senator since 1992.

“If he refuses to withdraw and wins, the Senate should vote to expel him, because he does not meet the ethical and moral requirements of the United States Senate,” Gardner said

That would prove to be a remarkable feat, given the last expulsion took place 155 years ago.

How is a senator expelled from office?

According to Article 1, Section 5, of the U.S. Constitution, the Senate can expel a member with a two-thirds vote after the Select Committee on Ethics launches its own investigation.

The committee would have to find grounds for the expulsion based on testimony from his accusers and other witnesses.

Beverly Young Nelson, who came forward on Monday to accuse Moore of groping her and trying to push her head toward his crotch when she was 16, said she would be willing to testify under oath. It remains unclear if the others are willing to do so.

How common is this?

Expulsion is very uncommon. A total of fifteen Senators have been expelled, the majority of which occurred during the Civil War for disloyalty.

Many congressmen facing expulsion in the last century have preemptively resigned.

Expulsion proceeds are being contemplated against Sen. Robert Menendez (D-NJ) who is currently being tried for corruption.

In 1995, the Committee on Ethics recommended Sen. Robert Packwood (R-OR) be expelled for “repeatedly committing sexual misconduct,” obstructing the committee’s inquiries, and seeking favors that would “enhance his personal financial position.”

Hours after the report was issued, Packwood resigned.