Suing the government is expensive work. That’s why federal law authorizes the “prevailing party” in a civil rights suit against the government to request attorney’s fees. But what happens if a court temporarily blocks a law as likely unconstitutional and the legislature then repeals that law? Do the law’s challengers qualify as “prevailing parties” because they got everything they wanted? Or must a court strike the final blow against a law for its challengers to qualify as “prevailing”? That is the question the Supreme Court will answer in Lackey v. Stinnie, and Cato has joined the Institute for Free Speech and several other organizations to file an amicus brief in the case.

In our brief, we argue that a party who receives a preliminary injunction against a law is the “prevailing party” if the government then repeals the law and leaves nothing further for the court to do. As our brief explains, civil rights litigation is designed to impact the law. When people cause the law to change in their favor, they “prevail” in every sense of that concept. Our brief thus urges the Supreme Court to adopt a bright-line rule: A party who wins relief at a preliminary stage of litigation “prevails” if it obtains an opinion that materially alters the law in its favor.

As our brief recounts, some of the most influential civil rights decisions in history never reached final judgment. Impact litigation is about setting precedents just as much as it is about winning a particular case. Many of the Supreme Court’s most important decisions were at the preliminary injunction stage, and it would be bizarre to say that the winning side in those cases did not qualify as the “prevailing party.”

Our brief also explains that the Supreme Court should eventually correct a doctrinal wrong turn. In a 2001 case called Buckhannon, the Supreme Court held that challengers to a law do not qualify as prevailing parties if the government ceases enforcement of the law before a court can even impose a preliminary injunction. Over the last 20 years, governments have exploited this rule to quickly moot cases and deny challengers the opportunity to obtain attorney’s fees. Impact litigation is frequently brought by nonprofits, and this strategy creates a serious obstacle to their ability to bring lawsuits that hold the government accountable.

While the Supreme Court does not need to overrule Buckhannon in this case, it should eventually do so to eliminate the government’s incentive to engage in gamesmanship. In the meantime, the Court should hold that a party can “prevail” by winning a preliminary injunction.