If Roy Moore wins tonight, will he get expelled? Probably not:
1. Republican senators, even ones hostile to Moore, have said for weeks now that it’s up to the voters of Alabama to decide. If Moore wins, he will immediately turn this argument around, “Hey, fellas, the voters of Alabama decided and here I am.” Like it or not, winning the election will lend legitimacy to a Senator Moore.
2. So will getting seated by the Senate and getting committee assignments, which will happen automatically.
3. The Ethics Committee will certainly look at Moore, but there is no guarantee that it will decide to delve into 40-year allegations.
4. Even if it does, it would be unprecedented for the Senate to expel someone based on conduct prior to his time as a senator. If Moore provably lied under oath in such a probe, that would be a current offense. But I would expect Moore to refuse to cooperate with an investigation, denounce it as a witch-hunt and say the voters of Alabama have already litigated the question.
5. No matter what happens, Trump is likely to strongly back Moore and oppose his expulsion. Such is his power in the party at the moment that he has a pretty decisive say in such matters.
6. The Republican base is likely to be skeptical of a Moore expulsion, not just because it would be over-turning the fresh verdict of Alabama voters, but because they would probably smell a preview of an attempt to impeach President Trump or to get him to resign over the allegations against him.
All of this makes it likelier than not — absent some explosive new revelation — that if Roy Moore makes it to Washington, he’s going to stay in Washington.