In the case of In re Borchert the Washington Supreme Court decided that a person tried before an unsalaried justice of the peace on a criminal charge was not deprived of due process of law because the justice was compensated on a fee basis.
Forest W. Walls,
Washington Justice Court System—Constitutionality of the Fee System of Compensating Justices of the Peace,
36 Wash. L. Rev. & St. B.J.
Available at: https://digitalcommons.law.uw.edu/wlr/vol36/iss4/11