Yes, any deliberative body requires a quorum to take valid actions. However, a quick reading of the Rules of the Wisconsin Legislature shows that a quorum is a simple majority unless a fiscal measure is being considered, in which case it is 3/5 of the house in question.
All the GOP has to do is separate the partial suppression of public employee collective bargaining measure from the budget measure and vote move to pass it, and the ‘Rats bluff is called. It is not a fiscal measure (as it does not deal with taxes, expenditures or borrowing) and for such measures a simple majority seems to constitute a quorum. They could top it off by quickly moving Constitutional carry, castle doctrine, voter ID, and half a dozen other non-fiscal bills the ‘Rats would loathe out of committee for immediate votes.
My understanding is that the limitations on collective bargaining do not even apply to wages negotiations, but only to “work rules, hours, etc.”
If union “work rules” explain why ten men stand around watching while another guy fills in a pothole, then that has a huge impact on government costs. The Dems can’t admit the work rules have that effect on costs, however, so they can’t claim it is an issue requiring the 3/5ths quorum.
I agree with you that the GOP senators should take advantage of the situation to pass their entire agenda. They could do a lot to effectively reduce government costs without cost cutting or budget issues being the explicit goals. Changing the eligibility and application requirements for foodstamps, Medicaid, and other welfare programs comes to mind. They could remove regulations so there are fewer government employees required to verify compliance. Require certifications for government employees that they don’t have and so they are no longer qualified for their jobs. Remove regulatory burdens from businesses to attract them to the state. There’s lots of stuff they could do without the Dems present, and they should get cracking.