You can not expell a new senator .
A legal expert on Rush said there is no method system .
Is a lie from Mitchy poo .
Please see the Constitution, Article 1, Section 5:
Each House may determine the Rules of its Proceedings, punish its Members for disorderly Behavior, and, with the Concurrence of two-thirds, expel a Member.
THEY DETERMINE THE RULES.
They could make a rule that "disorderly behavior" occurred prior to Moore's election (40 years ago), and Moore is forthwith expelled uponelection.
I don't like it, either, but the Founders gave a lot of power to the Senate. They tried to limit it by having them selected by the State legislatures, but of course the damned (I used that word advisedly) 17th Amendment ruined that.
Constitutionally they can; Article I, Section 5. The Constitution does not even say that the expulsion has to be done for cause. Realistically, unless McConnell & Co. have a good and valid reason for the expulsion then I doubt it would withstand the court challenge.