Too late for that, constitutionally. They had their chance in 2014. Now we're all stuck with the SOB until 2020.
The only way to get rid of him is for the Senate to expel him. And that's not gonna happen.
2016 / 2022
I appreciate your point but the psychological trajectory he is on will eventually manifest itself is increasingly bizarre behavior. At some point people in the state will need to convince him to leave before he totally embarrasses them with his quixotic antics.
The Senate itself may decide that he is embarrassing the institution (as hard as that is to do) and encourage him to call it a day. They wouldn’t impeach a war hero, but they would find a way to tell him its time to go.
Giant Meteor!