According to the Legislative Reference Bureau's review of Governor Scott Walker's proposed list of litigation reforms (.pdf; 31 pgs.):
In Thomas v. Mallett, 2005 WI 129, the Wisconsin Supreme Court held that the manufacturers of white lead carbonate, which was used as a pigment in paint, were liable for the injuries caused to a child who had ingested paint that contained the white lead carbonate, although the child could not prove that a particular manufacturer produced the white lead carbonate that he ingested.That isn't what the court held. The court held that the Wisconsin constitution did not bar the child from pursuing his case against the pigment manufacturers even though he had already won a judgment against the buildings' landlords and that the child could pursue that case according to the theory of risk contribution established in an earlier (1984) Wisconsin Supreme Court case, Collins v. Eli Lilly Co.
Similarly in Collins, the plaintiff could not identify the specific manufacturer of synthetic estrogen her mother was prescribed and had taken during her pregnancy and which caused Collins' injuries.
The Mallett court further held that the child's other claims of conspiracy and enterprise liability were faulty and could not proceed. But that court did not "hold" that any paint pigment manufacturers were liable, properly leaving that determination to the trial court.
It's also noteworthy that the two dissenters in Mallett, Justices Wilcox and Prosser, "recognize[d] the validity of the risk-contribution theory of recovery articulated by this court in Collins." What they objected to was its extension and application to the facts in Mallett.
Even the dissenters — who were as forceful as could be — affirmed only that the pigment manufacturers "can be held liable for a product they may or may not have produced" and only then as one (potential) "result" of the majority's reasoning. Emphasis added. And in fact they weren't, because the action the Mallett court allowed the child to continue against those manufacturers was ultimately dismissed.
It may be a fine distinction but it's an important one.
There is a big difference between saying that a court held a defendant liable and saying that a court held that a plaintiff is not constitutionally barred from continuing to pursue a claim based on a legal theory previously accepted and established by the State Supreme Court and, indeed, accepted by the dissenters in Mallett.
So in a very real sense, as Governor Walker and his corporate sponsors attempt to sweep the application of risk contribution theory entirely from Wisconsin courts, they are not only admonishing the Mallett majority, but also the two "conservative" Mallett dissenters, for having accepted the risk contribution holding in Collins.*
And in another very real sense, Thomas v. Mallett was about an injured party's access to justice and reasonable minds may differ, as they say, over whether Mallett inappropriately expanded that access, or whether Governor Walker's proposals inappropriately curtail it.
* There's a Supreme Court election meme for you: "Scott Walker slams Prosser for embracing outlandish liberal activist doctrine."