Amicus briefs, Latin for “friends of the court,” allegedly date back to the Roman Empire, when interested parties wrote to judges to advocate for certain legal issues or people. The first amicus brief filed in the Supreme Court was in 1823 by former secretary of state and House Speaker Henry Clay.

The modern version of amicus briefs started in the mid-1900s when the American Civil Liberties Union and other civil rights and consumer protection groups began filing the briefs with the Supreme Court and federal courts. In 1971, as left-leaning political groups racked up legal wins, Lewis F. Powell Jr, a corporate lawyer and future Supreme Court justice, wrote a memo to the Chamber of Commerce and other business lobbying groups urging them to hire a “highly competent staff of lawyers” to file similar briefs on behalf of the corporate world.

Since then, the Chamber and the National Association of Manufacturers, a trade group representing 14,000 companies in a wide range of sectors, have coordinated amicus brief efforts to gut campaign finance laws and promote private sector interests in the courts and Congress.

Over the past fifteen years, amicus briefs have proliferated, with groups filing briefs in 96 percent of all Supreme Court cases. These efforts are getting noticed; in 2023, justices cited amicus briefs in their opinions 145 times.

This system is fueling a cottage industry. The cost of amicus briefs can range from $15,000 to $80,000 or more, depending on the prestige of the legal groups involved and the stakes of the court case. For Supreme Court cases, the costs can be much higher.

The vast majority of this spending is done in secret, with little transparency about who is funding these influential judicial pressure campaigns.

For years, Sen. Sheldon Whitehouse (D-RI), has been sounding the alarm on the issue. As he noted in a 2024 letter he coauthored with Rep. Hank Johnson (D-GA), dark money interests fund legal groups that seek out certain plaintiffs “for strategic reasons” in order to advance the cases through a sympathetic federal court system.

Then, the lawmakers note, additional legal groups “file amicus briefs aligned with the litigating group.”

“Often, they file in orchestrated and harmonized flotillas” that can range in number from 10 to 55 briefs, Whitehouse and Johnson wrote.

The lawmakers continued: “In sum, a robust and coordinated system operates to flood appellate court proceedings with covertly funded amicus encouragement, while denying courts, the parties, and the public essential knowledge to evaluate the true interests behind the briefing and any resulting conflicts.”

For these reasons, Whitehouse and Johnson believe that the amicus brief disclosure rule is needed.

“Without transparency, wealthy donors and corporate interests can covertly fund dozens of seemingly distinct amici — as well as the ‘scholarship’ and ‘studies’ those amici cite in their briefs — to create the illusion of credibility and broad support where none exists,” wrote Whitehouse and Johnson in a comment letter on the rule.

A subcommittee of the Judicial Conference, a panel of senior federal judges including the chief justice of the United States that decides policy for the federal court system, proposed the new disclosure rule in August 2024. The rule would require amicus brief filers in the federal court system to disclose relationships they have with people involved in the case in question. The groups would also have to disclose any money given to them to prepare or submit the brief and “name any person who contributed or pledged to contribute more than $100 intended to pay for preparing, drafting, or submitting the brief,” unless they have been involved with the operation for more than a year.

The rule would also limit briefs to no more than 6,500 words and require groups to disclose who worked on the brief and for how long, among other matters. According to experts, the most consequential part of the rule change is the disclosure of donations earmarked for amicus briefs.

“Earmarked contributions run the risk that the amicus is being used as a paid mouthpiece by the contributor,” the Judicial Conference’s subcommittee wrote in an explanation for the rule change. “Knowing about earmarked contributions helps courts and the public evaluate the arguments and information in the amicus brief by providing information about possible reasons for the filing other than those explained by the amicus itself.”

Now that the comment period for the proposed rule change is closed, an advisory committee will read through the 407 comment letters submitted to the Judicial Conference — including those from a number of high-profile amicus brief filers.

That includes the Chamber of Commerce, the nation’s largest lobbying group, which wrote that the new rule updates are “unnecessary, counterproductive, and threaten to have a chilling effect on amicus organizations.” The Chamber also claimed that forcing groups to disclose their donors would violate the First Amendment.

The Chamber has long been one of the country’s most prolific amicus brief filers. In 2023, it bragged that it racked up “a 78% win rate in decided cases” where it had filed an amicus brief with the Supreme Court. During the last Supreme Court session, the Chamber filed twenty-eight amicus briefs in cases that, among other things, helped criminalize homelessness and roll back environmental protections.

The National Association of Manufacturers, a trade group representing 14,000 companies in a wide range of sectors, also filed a comment letter, claiming that there is no need for judges and the public to know who is funding amicus operations.

“The U.S. Supreme Court has described campaign disclosure laws as necessary for voters to know more about a political candidate so that voters can form judgments about how a candidate might act upon assuming office,” wrote the lobbying group. “By contrast, courts need not know who contributes to an organization or amicus brief to make the correct decision in a case.”

But according to the Judicial Conference committee that issued the rule, courts and judges do have an interest in knowing the identity and funding of the associations behind amicus briefs they read.

“Some have suggested that information about an amicus is unnecessary because the only thing that matters about an amicus brief is the merits of the legal arguments in that brief,” the committee wrote in a preliminary draft of the proposed rule. “At times, however, courts do consider the identity and perspective of an amicus to be relevant. For that reason, the Committee thinks that some disclosures about an amicus are important to promote the integrity of court processes and rules.”

Even if the advisory committee approves the disclosure rule, it faces an uphill battle for approval. The rule must also be green-lit by another subcommittee as well as the broader Judicial Conference, which has a conservative majority. Then it would be sent to the Supreme Court — which has a conservative majority due in part to Leo’s dark money campaigns — and then finally to Congress, which has its fair share of dark money supporters.

If the rule is approved by everyone involved, it could go into effect by December 2026.

Leo, the judicial power player, has used his network of dark money groups to fund the generation of numerous amicus briefs filed with the federal judiciary.

In 2014, a representative from the conservative nonprofit Bradley Foundation emailed Leo asking if there was a dark money nonprofit working on Supreme Court amicus briefs that it could donate to. Leo directed the Bradley Foundation representative to give to the Judicial Education Project, a dark money nonprofit founded by Leo that changed its name to the 85 Fund in 2019. The Bradley Foundation eventually paid the project $150,000 for its work on two amicus briefs — one of which was for a case challenging the Affordable Care Act — according to a 2021 letter from Whitehouse and Johnson.

Leo’s influence also extends to at least four groups — the American Legislative Exchange Council, the Pacific Legal Foundation, Americans for Prosperity, and Young America’s Foundation — that filed comment letters with the Judicial Conference opposing the new amicus brief disclosures, all claiming the rule violates the First Amendment.

Donors Trust, a major beneficiary of Leo’s dark money connections, gave nearly $3.5 million to four of these groups in 2023, according to tax filings.

Tax filings for 2023 show that the 85 Fund, which has close financial connections to Leo, donated more than $576,000 to the American Legislative Exchange Council, a conservative nonprofit that distributes model state and federal legislation on behalf of its donors. The Concord Fund, another Leo-connected nonprofit, also donated $100,000 that year to the American Legislative Exchange Council.

Americans for Prosperity, a nonprofit organization founded by right-wing petrochemical billionaires Charles and David Koch, has been at the forefront of the fight to hide nonprofit donors. In 2021, the nonprofit won a Supreme Court decision that struck down a California law requiring nonprofits to disclose the names and addresses of their largest donors.

In its comment letter on the new amicus brief rule, Americans for Prosperity claimed the disclosure of donors is not in the interest of the public or the government.

“Mere public curiosity is not a substantial governmental interest,” the group wrote. “Further, this informational curiosity is just as likely to misinform as inform the public.”

These claims echo similar arguments made by Sens. Mitch McConnell (R-KY), John Cornyn (R-TX), and John Thune (R-SD), who in their comment letter mocked the idea that dark money and financial interests were attempting to persuade the federal judiciary.

“The Democratic theory is that the federal judiciary — and the Supreme Court in particular — has been the target of a long-standing ‘scheme’ by private interests to take it over for their personal benefit,” the senators wrote. “In short, the Supreme Court doesn’t issue originalist rulings because it’s majority originalist; it does so because ‘right-wing special interests’ have ‘captured’ it.”

The senators also issued a warning: “If this rule is somehow enacted, we encourage affected parties to challenge it immediately in court.”

One traditionally liberal civil rights group is also opposed to the Judicial Conference rule. The American Civil Liberties Union, which also supported the 2010 Supreme Court Citizens United decision to allow limitless campaign spending by corporations and unions, believes that the amicus disclosure requirements would “burden First Amendment associational rights,” the group stated in a comment letter.

Other groups and lawmakers disagree. They see value in disclosing who is funding amicus briefs and any potential conflicts of interest involved.

Court Accountability stated in a comment letter that amicus briefs “can often act as alter egos” of the parties involved in a case, and that these parties can use amicus briefs to “misguide a court — and the public — by appearing independent from parties.”

In their own comment letter on the disclosure rule, Whitehouse and Johnson note that even corporate interests opposing the rule concede amicus briefs can persuade the courts.

“Even the Chamber of Commerce, which opposes the amendments, acknowledges that ‘assessing the sheer number of amicus briefs filed in a particular case can be useful’ to courts,” the lawmakers wrote in a comment letter. “Courts can find the number of amici in a case persuasive, and that when amici show up in flotillas to echo the same arguments, it can place a thumb on the scale in favor of the party they support.”