I confess I haven't looked around the web to find out for myself (such being the state of research needed for a blog post on this site at least), but it occurs to me that Gov. Walker has an option to resolve the Wisconsin state Democrat Senator's walk-out to prevent a vote from taking place.
What if the Gov had a quiet search done today and tomorrow so that he had individuals present in the state's Capitol for Monday morning, 21 Feb. At that time, he has the absent Senators declared to have abandoned their office and appoints the selected replacements to complete the abandoned terms of office (or 'till such time as a special election can be arranged, whichever best comports with state legal requirements).
Immediately post swearing in, the Senate leadership calls a quorum of the Senate with all the new members voting either "present" or "NAY" if they should feel a final reading of the statute in question is insufficient to their being fully informed enough to vote "AYE". Directly after that (and I mean the Governor is literally standing in the back of the same room the vote takes place in), Mr. Walker signs the bill into law while the newest members of the Senate make lunch reservations and firm-up their schedule to hold public meetings in their respective constituencies.
Too simple. There's bound to be some law already on the books to prevent such a straight-forward resolution to the purely political extortionate move the Democrats have elected to use (again - I remember the Texas Dem's running for the Oklahoma border to avoid their state and US Constitutionally mandated duty to vote on electoral redistricting following the last census).
Wisconsin state cops can't just go arrest them in Illinois (understandably enough the Illinois cops would object - however reluctantly). None of the scoff-law Senators has actually been convicted in a court of law as of yet, so siccing bounty hunters on them is out. And some citizen kidnapping one of them annonymously and delivering the corpus electus to some place inside Wisconsin's state line is just too Ian Fleming to contemplate (you watch - having just written that, someone will actually pull it off now. You wait ... :)). So what else can a "mere" state governor stoop to?
Frankly, this whole the law is whatever is convenient to our immediate objective political attitude so many of our elected representatives seem willing to resort to so egregiously in recent years, has me aggravated to the point that I'm more and more uncaring regarding the method's chosen to enforce their attention to their elected duty. That attitude is dangerous as well, especially if it is becoming as wide-spread amongst the general populace as I fear it might be becoming. Not too much further down that road, we all start shooting at each other over merely perceived differences of opinion and belief, never mind actual actions taken. We did that at least once before in this country's history (if you want to take the measure down to the level of local/regional riot, I'm not certain an accurate count of the total number of events even exists); what say we all do what's necessary to avoid repeating the exercise, shall we?