In the 1972 case of Ward v. Village of Monroeville, the U.S. Supreme Court ruled that a defendant's right to a fair trial was violated when his traffic violation and other misdemeanor cases were heard by a mayor who also had executive responsibilities for village finances. The court found that because fines from such violations made up a significant portion of the village revenue, this created an unconstitutional potential for bias in favor of conviction on part of the mayor-judge. This decision extended previous rulings about judicial impartiality into non-criminal proceedings and reinforced principles regarding separation between judiciary and executive functions within local governments.

In the dissenting opinion for Ward v. Village of Monroeville, Justice White argued that there was no constitutional violation in allowing a mayor to preside over traffic cases even if he also had responsibilities related to town finances. He believed that the majority's decision expanded due process requirements beyond what was necessary or intended by the Constitution. According to him, it would be impractical and unnecessary to require complete separation between judicial functions and other governmental roles in every situation as this could potentially invalidate many small-town court systems where such separations are not feasible. Furthermore, he pointed out that there were already safeguards in place against bias since defendants could appeal decisions made by mayors' courts.