Maybe they could be declared dead after they've been missing for awhile. Maybe they could be declared "politically dead" (sort of a variant of brain dead).
It's time for their affairs to be wrapped up.
What about “unable to do their duties”? Being in a hotel out of state would make them unable to do their job. Seems to me that an election could be called or something. These people are refusing to do what they were elected to do. So, something has to be done.
It is one thing to have a differing opinion, but you must show up and do what the people asked you to do.
As President Obama was fond of saying, “elections have consequences.” Walker won.