If Moore wins, Franken stays. If Moore loses, Franken delays leaving as long as possible. It may depend on whether the GOP elite and the Democrats decide to join forces to try to drive Trump out on the basis of the women's allegations (two saying that he kissed them, one that he "made her feel like a piece of meat"). I'm sure that's exactly the kinds of things the Founding Fathers had in mind when they specified "high crimes and misdemeanors" as grounds for impeachment.
The GOP elite would like Trump gone...but are they willing to commit political suicide in pursuit of that goal?