It’s been 155 years since the Senate expelled a member. Will Roy Moore break the streak?

On Monday, U.S. senators began publicly discussing the possibility of expelling Republican Roy Moore if he wins the December special election in Alabama. Moore, who has been accused of sexually harassing and assaulting underage girls, would be the first U.S. senator expelled from the chamber since 1862, during the Civil War.

That ignominious honor befell Democrat Jesse Bright of Indiana, who was ejected on Feb. 5, 1862, for disloyalty to the Union. He was the final of 15 members booted from the chamber in a sort of Senate housecleaning that followed secession and the onset of civil war. Newly elected anti-slavery Republicans furious at proslavery Democrats and Confederate sympathizers sought to punish all who did not resign voluntarily. Bright was the only Northerner included in the cleansing.

The comparison is imperfect. But the extreme circumstances of Bright’s ouster should indicate to Americans today how odious the current Senate finds Moore. So odious, in fact, that should Moore be expelled, it will be with the approval of his own party. Such a move hasn’t been successfully attempted in 155 years. That Republicans are now considering it suggests that the GOP in 2017 is facing a potentially fatal crisis, one not unlike Democrats in 1862.