The thing is, I think he believes he can win reelection. He may be working toward that goal and isn't willing to burn too many bridges.
If the House votes to expel him, and if he wins relection, the House will immediately expel him again. He's toast.
Can you imagine a House of Representatives condoning the fact that a MEMBER is operating from a federal prison? Won't happen.
Too young to remember Adam Clayton Powell?
Probably not.
But keep in mind--Boston's Mayor James Michael Curley served four terms as mayor--plus four terms in Congress, one term as Massachusetts governor and two terms in jail.