They can. They can also decide not to. It is their prerogative. If they don't pass the laws you want and disaster ensues, well, maybe Congress can quarantine the entire State. There is plenty of recourse.
EDIT: And what about South Dakota, which never shutdown? Or Georgia, which has re-opened? Or Texas, which is re-opening? What is so special about Wisconsin?
Which doesn't answer the question if they
have. This isn't some partisan bill but a force of nature, and if they are flexing their powers for the sake of posturing then more Wisconsin citizens will die if there isn't a plan presented by the "powers and perogatives" of legislature.
Nonsense. See South Dakota, Georgia, etc. If just one State not doing what you think they should be doing spells disaster for the U.S. (and the world), then we've already crossed that Rubicon.
EDIT: And what about South Dakota, which never shutdown? Or Georgia, which has re-opened? Or Texas, which is re-opening? What is so special about Wisconsin?