In my defence, the Wisconsin Senate rules do state fairly clearly:
Senate Rule 15. Roll call, quorum. [...] A majority of the membership presently serving must be present to constitute a quorum for the transaction of business; a smaller number, however, can adjourn and may compel the attendance of absent members.And I would not have been satisfied with just that, as I knew various States had supermajority requirements for certain special types of legislation, like California's infamous two-thirds requirement for its Budgets. So I had also dug up this, from the National Conference of State Legislatures, which clearly lists Wisconsin as able to pass its budget on a legislative majority basis.
All that said, clearly I missed something important. That being Article 8, Section 8 of the Wisconsin State Constitution, which says:
Article VIII, §8I drew the line at reading 50 State constitutions (a guy can only take so much!) and relied on other sources like the NCSL to point out such land mines of supermajority requirement. Looking at this, while it is technically true that Wisconsin's Senate does not allow "filibusters" in the narrow way that term is understood (protracting debate) and it is also technically true in the NCSL's defence that a straight majority vote, once held does pass the budget in Wisconsin, it still remains that minorities larger than two-fifths of either chamber can prevent business and thus prevent passage of something they are united against. Given how widely this language is written, it covers a great deal of legislation and all of the most important stuff. It also doubles the veto-points by granting this power to the minority of either Chamber.
Vote on fiscal bills; quorum. Section 8. On the passage in either house of the legislature of any law which imposes, continues or renews a tax, or creates a debt or charge, or makes, continues or renews an appropriation of public or trust money, or releases, discharges or commutes a claim or demand of the state, the question shall be taken by yeas and nays, which shall be duly entered on the journal; and three-fifths of all the members elected to such house shall in all such cases be required to constitute a quorum therein.
I don't know the history of this provision but my guess based on the history of these things is that it's another aristocratic relic - a way for the wealthy to more easily prevent the masses from taxing or spending their money. This makes the use of it by WI Senate Dems some nice poetic justice, to put one of these "keep the liberals from doing so much damn good" measures into actually supporting the greater good.
This only works because Republicans are trying to repeal some existing government support for the little guy, if the law didn't support public sector unionization, Republicans could just as easily use this sort of provision to prevent it from passing.
I'm also a little worried because it looks to me like a stand-alone bill repealing public sector collective bargaining rights could be passed without the three-fifths quorum so long as such a bill didn't spend any money.
Last to address the inevitable (general) claims that "you liberals were against minority obstruction when it was to your advantage now you are for it" - my take is that I would be happy to see this provision stripped from the Wisconsin State constitution. However, while it is there, I do not claim Democrats must unilaterally disarm and never obstruct majority business where the rules allow them. The "founders" of Wisconsin saw fit to give the minority the power to block spending bills by physically leaving the Chamber and the State, and Democrats believe this issue is sufficiently important to take such an extreme measure to prevent it. If they fail to stop something the rules allow them to, they are complicit. If the rules did not allow them to stop this, then voters could decide if they approved in 2012.
I also thought Democrats should have filibustered Alito and by not doing so, they still bear some responsibility (and ill will among the base) for each and every odious decision he joins. If Democrats had filibustered Alito, Republicans would probably have invoked the nuclear option and confirmed him on 51 votes. Aside from the upside of ending the filibuster, they would not bear the stain of failing to stop something awful. Wisconsin Democrats may lose this fight, but they will "lose well" in a way that builds for the future and leaves their hands clean.