In Bullock v. Carter, 1971, the United States Supreme Court ruled that Texas's filing fee system for primary elections was unconstitutional because it violated the Equal Protection Clause of the Fourteenth Amendment. The case arose when two potential candidates could not afford to pay high fees required to run in a Democratic primary election in Texas. The court held that these fees were discriminatory against less affluent candidates and their supporters as they effectively barred them from participating in an integral part of the electoral process - primaries which often determined final winners due to one-party dominance at that time. Therefore, this decision significantly impacted campaign finance laws by prohibiting states from setting prohibitively high ballot access costs.

In the dissenting opinion for Bullock v. Carter, Justice Black argued that Texas's filing fee system did not violate the Equal Protection Clause of the Fourteenth Amendment. He contended that there was no evidence to suggest that these fees were designed or used to discriminate against any identifiable class of candidates or voters based on wealth. Instead, he saw them as a legitimate means for states to recover administrative costs associated with elections and prevent frivolous candidacies. Furthermore, he pointed out that many other aspects of running a campaign also require significant financial resources and are not considered unconstitutional simply because they may be more burdensome for less affluent individuals or groups. Therefore, in his view, it was inconsistent and arbitrary to single out filing fees as being uniquely problematic from an equal protection standpoint.