When the administration of President George W. Bush sought legal justification for “enhanced interrogation techniques” such as stress positions, sleep deprivation, and waterboarding, it needed to get around the firm prohibition of torture in international law. One of its strategies was to claim that international law has limited authority over the United States. Brett Kavanaugh, President Donald Trump’s nominee to replace Anthony Kennedy on the Supreme Court, holds a stark version of this view. His confirmation would threaten the protection of fundamental human rights, including the right not to be tortured.

Torture is prohibited by customary international law and several treaties ratified by the United States. My book, The Promise of Human Rights, argues that a longstanding policy of marginalizing international human rights law facilitated the United States’ use of torture after 9/11. The battle over the domestic authority of international human rights law is still being waged in Congress and the courts.

Trump once vowed that he would “bring back waterboarding and … a hell of a lot worse than waterboarding.” The composition of the Supreme Court may determine whether he or a future president could act on this promise. While torture is prohibited by congressional statute, international law provides vital reinforcement. Bush administration lawyers proved adept at manipulating loopholes in federal anti-torture legislation.

The Bush administration almost succeeded in creating a permanent legal framework for unhampered detention and interrogation policies. Resistance from the Supreme Court was belated and partial, and the addition of one or two supportive justices would have given the Bush administration a free hand. In four major cases, Justice Kennedy voted with narrow majorities to restrain the government’s treatment of foreign captives.

Two of the four cases relied crucially on international law norms. In Hamdi v. Rumsfeld (2004), Justice Sandra Day O’Connor invoked international law principles to hold that Congress’s authorization of military force after 9/11 could not justify “indefinite detention for the purpose of interrogation.” In Hamdan v. Rumsfeld (2006), Justice John Paul Stevens ruled that detainees in what the administration had called the “war on terror” were entitled to basic humanitarian protections of Common Article 3 of the Geneva Conventions.

“Not Part of Domestic U.S. Law”

Several opinions that Kavanaugh has issued as a judge on the D.C. Circuit Court of Appeals suggest that he would have voted contrary to Kennedy. Of particular note is his position on international law, spelled out in a lengthy minority opinion in the 2010 Guantánamo case of Bihani v. Obama. Ghaleb Nassar al-Bihani, captured while serving as a cook for a Taliban-allied militia, claimed that his detention violated international law. Kavanaugh rebuffed this argument on the grounds that international law norms, unless written into congressional statutes or included in a limited subset of U.S. treaties, “are not part of domestic U.S. law.”

Kavanaugh’s claims are controversial. The United States’ international law obligations derive principally from its treaty commitments and from customary international law, a set of rules originating in a general practice and normative consensus among states. Kavanaugh’s position that international law norms are generally not part of domestic law conflicts with language in the Constitution declaring that “all treaties” made by the United States “shall be the Supreme Law of the Land.” It is also contrary to a long history of Supreme Court decisions, including O’Connor’s opinion in Hamdi. One of Kavanaugh’s controversial claims is that customary international law does not form part of domestic U.S. law. The Supreme Court has never taken this position, and has repeatedly stated the opposite.

The law of nations, as customary international law used to be known, is referenced in the Constitution. In the Federalist Papers, John Jay and Alexander Hamilton took it for granted that U.S. courts would have authority to enforce it, and Jay wrote as the country’s first Chief Justice that the United States “had, by taking a place among the nations of the earth, become amenable to the laws of nations.” In Murray v. the Charming Betsy (1804), the Supreme Court ruled that, whenever possible, statutes should be interpreted so that they comply with the law of nations. Arguably, Kavanaugh’s most controversial claim in Bihani is that courts should no longer apply customary international law via the Charming Betsy rule.

Customary international law is a central pillar of the prohibition of torture. In the 1980 case of Filartiga v. Pena-Irala, a federal appeals court judge ruled that, under customary international law, “the torturer has become – like the pirate and slave trader before him – hostis humani generis, an enemy of all mankind.” The judge consequently affirmed that foreign torture victims could seek civil remedies in the U.S. under the Alien Tort Statute, a 1789 law permitting lawsuits by non-citizens for torts committed in violation of the law of nations.

Last August, three torture victims used the Alien Tort Statute to win a settlement against two CIA contractors who had conceived and designed the U.S. torture program. But the Filartiga precedent has been challenged, and Kavanaugh’s views suggest he might join those seeking to end the use of the Alien Tort Statute for making human rights claims.

“Battlefield Preemption”

Kavanaugh’s own record on human rights lawsuits is troubling. In 2009, he joined an opinion that introduced a new doctrine of “battlefield preemption” to dismiss claims against private military contractors who had tortured prisoners in Abu Ghraib. It’s hard to find statutory authority for the majority’s argument, as Judge Merrick Garland pointed out in a forceful dissent.

Kavanaugh’s position on international law resembles some of the radical views that underpinned the notorious “torture memos” of the Bush administration. A secret January 2002 memo by John Yoo and Robert Delahunty claimed that “customary international law cannot bind the executive branch under the Constitution,” thus freeing the Bush administration to ignore the customary international law prohibition of torture. The same memo claimed that the president had constitutional authority to unilaterally suspend, contravene, or terminate treaties.

Kavanaugh served as associate White House counsel between 2001 and 2003 and White House staff secretary between 2003 and 2006. It’s unclear how much he knew about, and joined deliberations over, the administration’s detention and interrogation policies.

The nominee’s views place him in the company of the “New Sovereigntists,” the name given by legal scholar Peter Spiro on the eve of the Bush administration to a group of academics and policy analysts seeking to limit the authority of international law over U.S. policy. Among those profiled in Spiro’s 2000 article were John Yoo, a law professor who went on to join the Bush administration and write many of the torture memos, and Jack Goldsmith, another law professor who became director of the administration’s Office of Legal Counsel in October 2003. In June 2004, Goldsmith withdrew one of the principal torture memos and resigned in the fallout, but he did not withdraw authorization of the enhanced interrogation techniques previously approved on the basis of the memo.

Goldsmith had co-authored an influential Harvard Law Review article in 1997 challenging the authority of customary international law. Described by Spiro as “the opening salvo in the New Sovereigntist Crusade,” the article is invoked in the Yoo-Delahunty memo, and helps build the foundation for Kavanaugh’s Bihani opinion as well as a 2004 minority opinion by Justice Antonin Scalia arguing that the Alien Tort Statute may not be used to enforce customary international law.

While Goldsmith’s views have moderated over time, Kavanaugh situates himself at the far end of the New Sovereigntist movement. Goldsmith has argued that Congress’s post-9/11 authorization of military force does not authorize (though neither does it prohibit) acts that violate the international law of war. In Bihani, Kavanaugh expressly rejected any such interpretive limit on the congressional authorization of military force.

Kavanaugh does not even seem to think that executive and legislative officials are obligated to follow international law, for he writes in Bihani that they may choose whether or not to do so.

Kavanaugh’s radical views have momentous implications. A core purpose of international law is to shield individuals from the worst abuses of state power. If Kavanaugh is elevated to the Supreme Court, his insistence on marginalizing international law will severely undermine human rights.

Brett Kavanaugh meets with Senate Judiciary Committee member Sen. Ted Cruz (R-TX) in July 2018 in front of a painting of President Ronald Reagan in Cruz’s office. (Photo by Chip Somodevilla/Getty Images)