Almost no other case has had such a significant impact on the constitutional meaning of campaign finance laws as Buckley v. Valeo. Analysts of the issue often divide the history of money in the federal electoral process into the pre-Buckley and post-Buckley eras, demonstrating that the 1976 Supreme Court decision introduced a new understanding of the regulation of campaign finance. Opponents of the FECA and its amendment argued that some limits on campaign donations and expenses severely violated the Constitution, as they endangered the First Amendment rights to freedom of speech and association. The First Amendment's clause referring to the right to express oneself, the right to decide about the amount of money spent in a campaign by the candidate, and the right to information concerning the candidates, led to the very original conclusion reached by the majority of Justices that “money talks,” and that, therefore, the process of spending money in electoral campaigns is a type of expression called political speech.

The lawsuit was filed by conservative Senator James Buckley against a former member of Federal Election Commission, Francis Valeo, who represented the U.S. government. When the District Court and Court of Appeals decided against Buckley, he appealed to the Supreme Court, which granted review. The main issue in the case referred to the constitutionality of the provisions of the 1971 and 1974 legislation, which imposed expenditure limits on candidates in federal campaigns, but the Court, in a per curiam opinion, determined not only the status of campaign spending but also of individual and group contributions to candidates. On the one hand, the Justices upheld contribution limits, explaining their important anti-corruption role, but on the other they found expenditure limits to be in contradiction to freedom of speech and expression. In other words, the American government, having an interest in fighting corruption, had a compelling state interest to impose limitations on contributions, but not on campaign spending. Moreover, several passages of the Buckley decision seem to contradict each other. For instance, if presidential candidates applied to use the public fund, the expenditure limit would be constitutional. But if they chose to reject it, they were free to spend as much as they wished.