In the case of Giaccio v. Pennsylvania, 1965, the U.S Supreme Court ruled that a Pennsylvania law allowing juries to impose court costs on acquitted defendants was unconstitutional. The plaintiff, Joseph Giaccio, had been found not guilty in two separate trials for traffic violations but was still ordered by the jury to pay court costs under this law. He argued that it violated his rights under both due process and equal protection clauses of the Fourteenth Amendment because it gave juries unrestricted discretion to inflict financial penalties without any standards or guidelines. The Supreme Court agreed with him unanimously (9-0), stating that such an arbitrary system could lead to discriminatory practices and abuses of power as there were no clear rules governing when costs should be imposed.

In the dissenting opinion for Giaccio v. Pennsylvania, Justice Tom C. Clark argued that the statute in question did not violate due process as it had been applied consistently and fairly by Pennsylvania courts for over 200 years. He contended that the majority's decision was based on a misunderstanding of how juries functioned under this law, asserting that they were not given unbridled discretion to impose costs but rather followed established guidelines set out by precedent and tradition. Furthermore, he pointed out that no evidence was presented showing any abuse or arbitrary application of this law against defendants who were acquitted. Therefore, he believed there was no basis for declaring it unconstitutional.