Supreme Court Importance Measured by Amicus Citation Frequency

Researchers are proposing a refined method to identify the most significant Supreme Court cases: quantifying the frequency with which the Court cites specific organizations that file amicus curiae, or 'friend of the court,' briefs. This approach aims to move beyond simply counting total brief submissions, addressing a prior observation that such counts often emphasize civil rights and 'culture war' issues.

The previous method, which tallied all amicus briefs, indicated that a large volume of filings signaled a case's importance to knowledgeable parties. However, researchers noted this measure often reflected cases generating public or political interest, rather than necessarily those posing the most complex legal questions. Some briefs, for instance, serve to signal an organization's involvement to its constituents rather than to directly influence the court's decision.

To differentiate persuasive briefs from those filed for other reasons, the new method focuses on 'reputational weighting.' This involves tracking how often the Supreme Court has cited a particular amicus filer in its opinions over the preceding five terms. The logic suggests that the Court's citation acts as an indicator of a brief's usefulness or influence; unhelpful or expressive briefs typically do not receive citations.

By tallying these citation counts for all filers in a given case, analysts can assign a 'reputational score.' Cases with many filers who have a history of being cited by the Court receive higher scores, suggesting their briefs contained information the justices found valuable. This metric excludes briefs filed by the United States government due to its frequent role as a party in cases and its disproportionately high citation rate, which could skew results.

Applying this new metric to recent terms reveals shifts compared to the raw brief count. In the 2024-25 term, *United States v. Skrmetti*, concerning state bans on certain medical treatments for transgender minors, ranked highest. *Smith & Wesson*, regarding Mexico's lawsuit against gun manufacturers, followed, with *Free Speech Coalition v. Paxton*, *Fuld v. PLO*, and *Tiktok v. Garland* completing the top five. These cases involve diverse legal areas including medical treatments, international law, and technology regulation.

The 2023-24 term saw *United States v. Rahimi*, addressing Second Amendment rights in the context of domestic violence restraining orders, at the top. *Loper Bright Enterprises v. Raimondo*, concerning agency deference, *FDA v. Alliance for Hippocratic Medicine* (on mifepristone regulation), *Trump v. Anderson* (presidential ballot eligibility), and *Moody v. Netchoice, LLC* (social media regulation) also appeared in the top five.

For the 2022-23 term, *Moore v. Harper*, which rejected the independent state legislature theory, led the list. This was followed by *303 Creative LLC v. Elenis* (same-sex wedding website design), *Gonzalez v. Google LLC* (social media speech regulation), *Allen v. Milligan* (Voting Rights Act), and *Students for Fair Admissions v. President and Fellows of Harvard College* (affirmative action).

Researchers note that this weighted approach often elevates cases focused on institutional stakes, administrative power, and economic regulation. Examples include *Moore v. Harper* and *Loper Bright Enterprises v. Raimondo*, which saw their ranks rise significantly under this new methodology. Cases such as *Trump v. United States*, involving presidential immunity, also gained importance, though an expedited timeline for brief submissions may have impacted its total number of filings.

The analysis also examined the prevalence of ideologically split decisions. Among the 15 top cases across three terms, five decisions were determined along ideological lines using the weighted method, a slight decrease from six under the raw count. For all above-median cases by amicus reputation, 29 out of 38 (74%) were not resolved along ideological divisions, indicating that a majority of significant cases do not reflect a consistent 6-3 conservative-liberal split.