Wisconsin constitution
Article I: declaration of rights
Section 5

The right of trial by jury shall remain inviolate, and shall extend to all cases at law without regard to the amount in controversy; but a jury trial may be waived by the parties in all cases in the manner prescribed by law. Provided, however, that the legislature may, from time to time, by statute provide that a valid verdict, in civil cases, may be based on the votes of a specified number of the jury, not less than five-sixths thereof.