Is it possible to expel people from the party?
No.
As for Antonio's comment, spot on. I'm not saying the AL Dems are going to regain their glory or anything, but Doug Jones' election (and, more specifically, Roy Moore's horribleness) are nothing but good news for the future of the Alabama Democratic Party - an organization that has only been able to look to the past for like 20 years now.
And, to an earlier statement, people like Bannon, Moore and even Trump are doing nothing but longterm damage to the GOP, and they're perfectly fine with it. "Sleeper agent" has too many connotations, but the effect is the same.
