The Cato Institute is one of the biggest filers of amicus curiae (Latin for “friend of the court”) briefs in the Supreme Court. These briefs are filed with the Supreme Court by third parties who have a special interest or expertise in a case and want to influence the Court’s decisions. In all our briefs, Cato maintains an unwavering commitment to articulating how the principles of liberty and a commitment to the original meaning of the Constitution should guide judicial decisions. Petitioners to the Supreme Court from all over the country now actively seek Cato’s support — so many that we turn away a good deal due to lack of resources.
Cato at the Supreme Court
Amicus briefs can either be in support of (or, very rarely, in opposition to) a petition for a writ of certiorari — known in legal shorthand as a “cert petition” — meaning that an amicus is advising on whether the Court should hear a case; or they can be “on the merits,” meaning that an amicus is making arguments on how the Court should rule in a case it has already agreed to hear. In recent years, amicus filings have exploded. For example, the constitutional challenge to the Affordable Care Act, NFIB v. Sebelius (2012), drew 136 amicus briefs (a record that would be broken just three years later in Obergefell v. Hodges, the consolidated same‐sex marriage cases, which entertained 149 amicus briefs).
Each year, thousands of petitions for a writ of certiorari are filed and only about 75 are granted. Among those thousands of petitions, only a few receive support from amici. Many academic studies have indicated that briefs at the certiorari stage have a greater impact on the Court — greater, that is, than just being another voice among the potentially dozens of briefs weighing in on the merits. Accordingly, since about 2014, Cato has consistently filed more briefs in support of certiorari than on the merits. We have also expanded our presence in the circuit courts of appeals, the level just below the Supreme Court, as well as in state supreme courts. In those courts, which receive far fewer amicus briefs than the U.S. Supreme Court, we are concentrating our legal firepower on upcoming issues.
Amicus briefs serve a variety of purposes. Some inform the justices about economic, historical, scientific, or sociological data. Those briefs can be useful in more esoteric cases that are difficult for even the best legal minds to understand (the justices aren’t experts on everything). For a case dealing with an adjustment in banking regulations, for example, it can be helpful for those who are more familiar with banking practices to tell the Court how those changes will work in practice. Other briefs can focus on a particular legal argument that is not fully explored in the merits briefs, or explain the scope of the problem that the Court is asked to address. For briefs supporting certiorari, it can be helpful to the Court to explain why a given legal issue requires the Court’s attention and why taking a particular case is the best way to resolve that issue.
Some amicus briefs — actually a significant number of them (particularly in the highest‐profile cases) — are just “me too” briefs. These filings merely restate the arguments for the main parties in different language. These are not helpful to the Court and are usually ignored.
At Cato, we actively avoid “me too” briefs. We work with the counsel for the parties we support, as well as other amici, to discuss what arguments need to be covered. To maximize efficiency and avoid redundancy, often we’ll join other organizations’ briefs rather than filing our own, or invite other groups to join ours. A properly coordinated array of amicus briefs will hit all sides of the argument, with little or no overlap, and provide information for the Court about the scope of the problem and the effects of possible rulings.
Because of effective lawyering and strategic amicus coordination, as well as a Constitution that, interpreted properly, is quite libertarian, the Supreme Court has been one of the few friends in government for advocates of individual liberty. For example, in the 2012–2013 term, the Court sided with Cato 15 times (out of 18 filings), seven of them unanimously. Cato also went three‐for‐three that term on the Court’s blockbuster, end‐of‐term cases: affirmative action (Fisher v. UT‐Austin), same‐sex marriage (United States v. Windsor), and the Voting Rights Act (Shelby County v. Holder). In fact, we were the only organization to support the constitutionally correct outcome in each of those cases, demonstrating that the libertarian view is truly a third way that is not represented by either progressives or conservatives.
With recent personnel changes on the Court, it seems likely that many arguments for limited government, separation of powers, and an effective system of checks and balances will be well received.
For a complete and constantly updated list of Cato’s amicus briefs, see here. For an annually updated tally of Cato’s amicus briefs, see the chart at the very bottom of this page.
Here is a sample of Cato’s notable amicus briefs:
McDonald v. City of Chicago (2009):
In 2008, in District of Columbia v. Heller, the Supreme Court confirmed what most scholars and a substantial majority of Americans long believed: that the Second Amendment protects an individual right to keep and bear arms. Heller led to a challenge to Chicago’s handgun ban, which raises the question of whether the Fourteenth Amendment protects that right against infringement by state and local governments.
The Seventh Circuit answered the question in the negative, finding itself foreclosed by 19th‐century Supreme Court decisions. The Supreme Court agreed to review the case and specifically consider whether the Fourteenth Amendment’s Due Process Clause or its Privileges or Immunities Clause is the proper provision for incorporating the Second Amendment right to keep and bear arms as against the states. Cato, joined by the Pacific Legal Foundation, filed a brief supporting those challenging the handgun ban and calling for an overruling of the Slaughter‐House Cases, which eviscerated the Privileges or Immunities Clause in 1873.
Slaughter‐House narrowly circumscribed the rights protected by the Privileges or Immunities Clause, contrary to the intentions of the Amendment’s framers and in direct contradiction to the developments in legal theory that underlay its adoption. In addition to ignoring the history surrounding the Fourteenth Amendment, the Slaughter‐House majority violated basic rules of constitutional interpretation. Restoring the Privileges or Immunities Clause would not result in the demise of substantive due process because the idea at the core of that doctrine — that the Due Process Clause imposes something more than mere procedural limits on government power — was widely accepted when the Fourteenth Amendment was enacted and its authors rightly believed that the distinct clauses would provide separate but overlapping protections.
Outcome: The Supreme Court voted 5–4 to extend the right to keep and bear arms to the states, a four‐justice plurality via the Due Process Clause and Justice Clarence Thomas, providing the key fifth vote, through the Privileges or Immunities Clause.
United States v. Jones (2011):
As technology advances — and law enforcement adapts these advancements to police work — are asked to apply the Fourth Amendment’s protections against unreasonable searches and seizures in new and varied situations. In 2004, the FBI, as part of a joint task force, suspected Antoine Jones of dealing drugs. To verify their suspicions, agents secured a warrant allowing them to attach a GPS tracking device to Jones’s car but then attached it after the warrant had expired, and in Maryland rather than the warrant’s operative jurisdiction of D.C. The FBI used this device to monitor and record the car’s every movement for nearly a month before finally arresting Jones.
The U.S. Court of Appeals for the D.C. Circuit found that the FBI’s action was unconstitutional because it violated Jones’s “reasonable expectation of privacy” — the two‐part Fourth Amendment standard developed in the landmark case of Katz v. United States (1967). The “reasonable expectation of privacy” doctrine holds that if a person has a subjective expectation of privacy and that expectation is one society is prepared to accept, then the Fourth Amendment protects the object of that expectation from government search. The court found that the long‐term round‐the‐clock GPS surveillance, even of a vehicle always on public roads and in locations readily observable by a cop on the street, was qualitatively different than a temporary stakeout or other conventional surveillance.
At the Supreme Court, Cato filed a brief supporting Jones and arguing that the case affords the Court an opportunity to revisit the “reasonable expectation of privacy” test — which has dominated this area of law but is increasingly unworkable. That test reverses the original meaning of the Fourth Amendment by putting the onus on citizens to prove the reasonableness of their expectations instead of examining the reasonableness of government action. By measuring the actions an individual takes to shield his information against the reasonableness of the government’s actions in piercing that shield, the Court can simplify this area of law from one measuring esoteric “expectations” to one examining a straightforward factual question. Moreover, the government’s conversion of Jones’s car into a surveillance device acted as an unreasonable seizure because it deprived Jones of a valuable property right, the right to exclude others from his property. Similarly, using his car to collect information and track Jones became an unreasonable search. Thus, we argued, even if the Court continues to adhere to the “reasonable expectations of privacy” test, it should recognize the sanctity of Jones’s property and find the warrantless GPS‐attachment and ‑surveillance unconstitutional.
Outcome: The Supreme Court unanimously ruled against the government, on three different theories. Justice Antonin Scalia, writing for five justices, held that installing the GPS device was a trespass intended to obtain personal information and thus constituted a search under the Fourth Amendment. Justice Samuel Alito, writing for four justices, found a conventional privacy violation under the Katz test. Justice Sotomayor concurred with Justice Scalia’s majority opinion, but wrote separately to suggest that the Court needed to update its Fourth Amendment jurisprudence for the digital age.
United States v. Windsor (2013):
One of the blockbuster cases of recent years concerned a challenge to Section 3 of the Defense of Marriage Act (DOMA), which defined “marriage” in all federal statutes as a union between one man and one woman. More than 1,000 federal statutes and regulations deal with the concept of “marriage” in some way, and under DOMA same‐sex couples who were legally married in their state were denied federal benefits. Edith Windsor, the plaintiff, was in a relationship with Thea Spyer for more than four decades when they legally married in Canada in 2007. Upon Spyer’s death in 2009, Windsor faced a federal estate tax of $363,053 because DOMA’s Section 3 prevented the IRS from recognizing Windsor as a surviving spouse. Windsor sued for a refund of the tax money.
In a case of interesting bedfellows, Cato joined the Constitutional Accountability Center (CAC) on a brief arguing that DOMA violated the Fifth Amendment’s guarantee of equal protection. The CAC is a think tank and public‐interest law firm dedicated to “fulfilling the progressive promise of our Constitution’s text and history.” Cato and CAC usually butt heads, most prominently on the Affordable Care Act, but this time we joined forces, once again proving the unique position of libertarian legal arguments.
The equal protection principle forbids the federal government from arbitrarily disfavoring a class of individuals under the law, the brief argued, which Section 3 did by discriminating against lawfully married individuals on the basis of their sexual orientation. DOMA was motivated by prejudice against homosexuals and in no way furthered any legitimate federal goals.
Outcome: A five‐justice majority agreed with Cato and CAC, holding Section 3 unconstitutional “as a deprivation of the liberty of the person protected by the Fifth Amendment.” Justice Anthony Kennedy, writing for the majority, held that the federal government cannot intrude into a state’s traditional role in recognizing marriages to bring disfavor onto an unpopular minority.
After supporting marriage equality for longer than nearly any institution in Washington, it was gratifying to see the Court adopt Cato’s position. This was a trailblazing decision and an important step on the road to equal rights for the LGBT community.
Susan B. Anthony List v. Driehaus (2014):
Believe it or not, it was illegal in Ohio to lie about politicians, for politicians to lie about other politicians, or for politicians to lie about themselves. That is, it violated an election law — this isn’t anything related to slander or libel, which has higher standards of proof for public figures — to make “false statements” in campaign‐related contexts.
During the 2010 House elections, a pro‐life advocacy group called the Susan B. Anthony List (SBA List), published ads claiming that then‐Rep. Steven Driehaus, who was running for re‐election, had voted to fund abortions with federal money (because he had voted for Obamacare). Rather than contesting the truth of these claims in the court of public opinion, Driehaus filed a complaint with the Ohio Election Commission (OEC) under a state law that makes it a crime to “disseminate a false statement concerning a candidate, either knowing the same to be false or with reckless disregard of whether it was false.”
While the complaint was ultimately dropped, the SBA List took Driehaus and the OEC to federal court, seeking to have this law declared unconstitutional and thus enable advocacy groups to have more freedom going forward. Joined by legendary satirist P.J. O’Rourke, Cato’s brief supported SBA List and reminded the Supreme Court of the important role that “truthiness” — facts you feel you in heart, not in your head — plays in American politics, and the importance of satire and spin more broadly.
We asked the Court a simple yet profound question: Doesn’t the First Amendment’s guarantee of free speech protect one man’s truth even if it happens to be another man’s lie? And who’s to judge — and on what scale — when a statement slides “too far” into the realm of falsehood? However well‐intentioned Ohio legislators may have been, laws that criminalize “false” speech don’t replace truthiness and snark with high‐minded ideas and “just the facts.” Instead, they chill speech, replacing the sort of vigorous political dialogue that’s at the core of the democratic process with silence.
Outcome: The Supreme Court unanimously held that SBA List had the right to challenge this censorship. On remand, the lower courts struck down Ohio’s law on First Amendment grounds.
Expressions Hair Design v. Schneiderman (cert‐stage 2016):
In Federalist 10, James Madison warned of “a number of citizens, whether amounting to a majority or minority of the whole, who are united and actuated by some common impulse of passion, or of interest, adverse to the rights of other citizens or to the permanent and aggregate interests of the community.” These groups — “factions” in Madison’s terms — come together to seek concentrated benefits from favorable legislation and regulation rather than competing in the marketplace, while spreading the costs throughout society.
The New York legislature provided an example of this when it ignored the First Amendment rights of both merchants and consumers and — at the behest of the credit‐card lobby — passed a law restricting how retailers can convey pricing schemes, as well as the public’s right to know about them. New York’s no‐surcharge law — like those in 10 other states — insulate credit‐card companies from consumer knowledge about who is actually causing the higher prices on goods when they use their credit card (“swipe fees”). The law does this not by restricting the merchants’ ability to charge different prices as between cash and credit payments — that’s legal everywhere — but by regulating the communications regarding the different prices. Put simply: the law allows merchants to offer “discounts” to cash‐paying customers, but makes it a crime to impose economically equivalent “surcharges” on those who use plastic.
By mandating how merchants convey their pricing structure, New York restricts speech on the basis of its content, which seems to be an obvious First Amendment violation. A district court agreed — as have two other federal courts, including the Eleventh Circuit when it struck down a similar Florida law. The court held that the law “plainly regulates speech” — not conduct — by drawing a line between prohibited “surcharges” and permissible “discounts” based solely on words and labels. The Second Circuit disagreed, however, holding that the law regulates “merely prices,” not speech. Cato filed a brief urging the Supreme Court to take up this important case and rule that collusion between business interests and state government can’t be used to circumvent constitutional rights.
Outcome: The Supreme Court granted cert and ultimately vacated the Second Circuit’s ruling, with instructions to reconsider the case in light of the important First Amendment issues at play.
Cato’s Annual Amicus Brief Filings
| Year | Total | Supreme Court Total | Supreme Court Merits | Supreme Court Cert‐Stage | Circuit Courts | District Courts | State/DC Courts |
| 2020 | 72 | 40 | 12 | 28 | 28 | 1 | 3 |
| 2019 | 87 | 62 | 9 | 53 | 20 | 3 | 2 |
| 2018 | 80 | 56 | 18 | 38 | 13 | 1 | 10 |
| 2017 | 75 | 57 | 16 | 41 | 13 | 0 | 5 |
| 2016 | 66 | 39 | 14 | 25 | 21 | 0 | 6 |
| 2015 | 57 | 37 | 13 | 24 | 16 | 1 | 3 |
| 2014 | 51 | 34 | 13 | 21 | 14 | 0 | 3 |
| 2013 | 49 | 39 | 20 | 19 | 6 | 2 | 2 |
| 2012 | 38 | 34 | 18 | 16 | 1 | 1 | 2 |
| 2011 | 34 | 24 | 12 | 12 | 9 | 0 | 1 |
| 2010 | 18 | 14 | 7 | 7 | 3 | 1 | 0 |
| 2009 | 25 | 26 | 16 | 9 | 1 | 0 | 0 |
| 2008 | 6 | 6 | 4 | 2 | 0 | 0 | 0 |
| 2007 | 4 | 4 | 3 | 1 | 0 | 0 | 0 |
| 2006 | 5 | 5 | 5 | 0 | 0 | 0 | 0 |
| 2005 | 8 | 7 | 6 | 1 | 1 | 0 | 0 |
| 2004 | 10 | 9 | 7 | 2 | 0 | 1 | 0 |
| 2003 | 5 | 4 | 3 | 1 | 0 | 1 | 0 |
| 2002 | 3 | 3 | 3 | 0 | 0 | 0 | 0 |
| 2001 | 3 | 2 | 2 | 0 | 1 | 0 | 0 |
| 2000 | 5 | 5 | 4 | 1 | 0 | 0 | 0 |
| 1999 | 1 | 1 | 0 | 1 | 0 | 0 | 0 |
| Total | 519 | 385 | 179 | 206 | 98 | 8 | 29 |