From the Boston Tea Party of 1773 to today’s Tea Party movement, from suffragettes to Occupiers, freedom of political association has always been this country’s hallmark. Importantly, this First Amendment freedom extends to campaign contributions. As the Supreme Court affirmed in the 1976 case Buckley v. Valeo,“the right of association is a basic constitutional freedom that is closely allied to freedom of speech and a right which, like free speech, lies at the foundation of a free society.”

The Buckley ruling has since survived many assaults—including, most notably, Citizens United v. FEC—though Citizens United exposed certain instabilities in Buckley’s framework. In any event, challenges continue to arise at the intersection of campaign finance law, political association rights, and the freedom of speech.

An important one comes from three individuals who have business contracts with the federal government. Under the Federal Election Campaign Act’s section 441c(a), “any person who is negotiating for, or performing under, a contract with the federal government is banned from making a contribution to a political party, committee, or candidate for federal officer.” Accordingly, the three plaintiffs are prohibited from making their intended campaign contributions and thus from an important form of political participation. This rule applies even to someone like name plaintiff Professor Wendy E. Wagner, who derives only a fraction of her income from the federal contract.

Together with the Center for Competitive Politics, Cato last week filed an amicus brief with the U.S. Court of Appeals for the D.C. Circuit, arguing that the plaintiffs should be able to exercise their right to political association and speech by contributing to political campaigns. Specifically, we argue that section 441(c) is unique in that it entirely bans contributions by a class of individual citizens.

In McConnell v. FEC,the only case where the Supreme Court addressed an outright ban on contributions by a class of individuals—the ban on campaign contributions by minors originally in the McCain-Feingold campaign finance “reform,” which McConnell otherwise substantially upheld—the Court struck it down as overly broad and because the government didn’t give sufficient justification. What’s clear from that ruling is that for a ban on political speech and association to be constitutional, the government must show that its targeted class of people is somehow too dangerous to be allowed to participate in the political process, and also that the ban applies only to that set of uniquely dangerous people. Section 441(c) doesn’t meet this test.

If the government wants to ban her from this important form of political participation, then it must give more than bare assertions of the specter of potential corruption.

The D.C. Circuit will hear argument in Wagner v. FEC on September 30.