McConnell actually has a technical argument he could make to block Moore
Article 1, § 5, Clause 2 of the Constitution --
"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."
These sort of allegations regarding Moore are just one example of why due process is mentioned more than once in the Constitution. But I am not sure if procedural or substantive due process would apply here, if McConnell tried this.