Pleasing Everyone And No One: Justice Kavanaugh’s Opinion in Trump v. Barbara

Introduction:
On June 30, 2026, the Supreme Court struck down President Trump’s infamous Executive Order 14160, in which he attempted to end birthright citizenship for those born in the United States to undocumented or temporarily present parents. Writing the majority opinion for the Court, Chief Justice Roberts grounds the Court’s decision in the Fourteenth Amendment's text—specifically, the language of the Citizenship Clause. Reaching the identical conclusion, that the executive order is unlawful, Justice Kavanaugh offers a line of argument far from that of the rest of the Court, relying on rather narrow statutory grounds; in doing so, the associate Justice seems to satisfy everyone, and no one, all at once. He hands liberals the result they wanted, but rather clearly accuses their constitutional reasoning of being particularly lackluster and incorrect. Moreover, he hands conservatives a striking theory that domicile-based exceptions to birthright citizenship—the crux of the discussion in the majority’s opinion—are constitutionally permissible, even though he declines to practically apply the theory here. In this somewhat convoluted maneuver, Justice Kavanaugh, whether intentionally or inadvertently, identifies and arguably suggests a viable route for the administration to enact their birthright citizenship restrictions, despite his vote in Barbara having just blocked the policy.

Case History:
Trump v. Barbara asked the essential question of whether the executive order the president signed mere days into his second term complies with the Citizenship Clause of the Fourteenth Amendment and with 8 U.S.C. § 1401(a), the federal statute through which Congress codified the clause. The order instructed federal agents to deny American citizenship to any child born in the United States to parents who are undocumented or maintain only temporary status in the country. The executive order, and broader question of birthright citizenship in light of recent immigration challenges in the United States, have plagued the country and quickly became a crucial focus of federal and state agencies, and the courts are no exception.

Barbara is the direct successor of Trump v. CASA, decided almost exactly one year earlier. After Trump signed the executive order in January 2025, three district courts immediately blocked it with universal injunctions—a form of relief that barred the enforcement of the order nationwide, not simply for the relevant plaintiffs. The government’s appeal in CASA challenged only that particular form of relief, rather than its substantive content or the constitutionality of the order. Writing for the majority in CASA, Justice Barrett’s opinion held that the Judiciary Act of 1789 doesn’t enable injunctions to reach beyond what’s needed to give named plaintiffs “complete relief.” However, CASA left the merits of the case, and the question of birthright citizenship, completely unaddressed.

It did, however, leave open one route to achieve nationwide relief: a certified class action under Rule 23 of the Federal Rules of Civil Procedure. Unlike a universal injunction which protects an unclear number of unnamed strangers, a certified Rule 23 class is a defined legal entity. A court formally recognizes the group on the grounds that the class is too large for individual suits, shares an identical legal question, and is—in its entirety—adequately represented by named plaintiffs. As such, a single judgment can properly bind them. The American Civil Liberties Union (ACLU) filed exactly this kind of suit in New Hampshire within hours of the CASA decision being handed down, subsequently becoming Trump v. Barbara. The district court in New Hampshire provisionally certified a nationwide class of children who would be denied citizenship under the order and preliminarily enjoined its enforcement on that basis. The Supreme Court granted the government’s writ of certiorari before judgment and heard the case on April 1, 2026. Having settled crucial procedure in CASA, the Court finally answered the substantive question of birthright citizenship in Barbara, which its predecessor pointedly declined to reach.

Justice Kavanaugh’s Opinion:
Justice Kavanaugh’s opinion in the case, concurring in the Court’s judgment while dissenting from its constitutional holding, opens exactly where he thinks the Court should have stopped. Enacted in 1940, and then reenacted in 1952, Section 1401(a) grants birthright citizenship to those “born in the United States, and subject to the jurisdiction thereof" — language directly lifted off of the Fourteenth Amendment. The Court had already interpreted that exact statutory phrase back in 1898 when deciding United States v. Wong Kim Ark, creating a general rule of birthright citizenship, with four narrow exceptions: children of foreign diplomats, children born on foreign public ships, children of hostile occupying forces, and children of tribal Native Americans. When Congress enacted that same language in 1940, and then again in 1952, Justice Kavanaugh argued it did so knowing exactly how the Court had already read it in Wong Kim Ark. Moreover, in his opinion, he asserts that courts have long presumed that when Congress enacts language that a court has already interpreted, it means to adopt the existing interpretation. In applying that presumption, Justice Kavanaugh bargained that Congress had secured the four Wong Kim Ark exceptions as a full and final list when writing § 1401(a).

Having to his satisfaction settled the case’s statutory question, Justice Kavanaugh turns to the constitutional question that lies at the heart of Trump v. Barbara — whether the four historical exceptions to birthright citizenship is an expandable list under new circumstances. The Justice is somewhat reluctant to address this question, invoking the doctrine of constitutional avoidance and preferring that the issue be resolved on statutory grounds alone — but reaches the question anyway, having felt that the majority forced the issue. Addressing the question, Kavanaugh acknowledged his agreement with the four exceptions set out by Wong Kim Ark, but disagreed that the particular set of four are a closed set, essentially frozen from their ratification with no room for change. Drawing strong analogies to the Fourth Amendment and its application to cars, the First Amendment and the introduction of the internet, and the Second Amendment and the creation of semiautomatic handguns, he argues that constitutional exceptions—similar to that of constitutional rules—should extend to new circumstances that are “relevantly similar” to what the Framers had in mind. In doing so, the Justice promotes a very particular kind of originalism, one that flexes rather than freezes, under which the original principle stays fixed but its application flexes to accommodate new facts that the Framers could have never foreseen. Justice Kavanaugh expresses that the mass illegal immigration the country has faced in recent years is a perfect example of these new circumstances.

Moreover, he pinpoints the unifying theme of each of the four Wong Kim Ark exceptions as parents not being U.S. citizens, and contends that the type of restrictions the administration is seeking to establish would extend naturally to a fifth exception. Notably, the approach bears a particularly striking resemblance to living constitutionalism, the exact theory that modern conservative originalism was developed to push back on. Justice Kavanaugh’s framework departs somewhat meaningfully from strict originalism’s static reading of the Constitution, even while it insists on preserving that text’s original principle.

Kavanaugh’s theory struggles to escape criticism of internal contradiction and an obvious tension arises within the opinion. Wong Kim Ark’s parents were Chinese nationals who, under U.S. law at the time, couldn’t become citizens, and Justice Kavanaugh has agreed that the case was rightly decided. Thus, if the unifying principle of the four Wong Kim Ark exceptions is parents who aren’t U.S. citizens, Wong Kim Ark himself should have been excluded from Fourteenth Amendment protections. He wasn’t, and Kavanaugh agreed that the Court got it right with its decision in 1898. As such, in practice the Justice’s opinion would require a definition of non-citizen parents broad enough to justify a new fifth exception for families targeted by Barbara, but not too narrow that it would have excluded Wong Kim Ark’s parents in 1898. Kavanaugh’s opinion doesn’t elaborate on a definition satisfying the two conditions. Chief Justice Roberts’ majority opinion noted this very contradiction rather directly, asserting that the distinction sits uneasily with the constitutional principle that Kavanaugh contended should be prioritized. Even so, the unresolved tension does little to disturb the case’s outcome, with Justice Kavanaugh joining the majority in their vote to strike down the President’s executive order.

Conclusion and Implications:
Putting aside Kavanaugh’s vote, the Justice’s opinion—whether intentionally or not—directs the administration to a clear constitutional framework through which they can invoke future legislation aiming to end birthright citizenship for those targeted by Executive Order 14160. Kavanaugh’s opinion specifically points to Congress, asserting that they could amend the federal statute, § 1401(a), and that such legislation “would pass constitutional muster.”

Hours after the ruling, President Trump seized on exactly this point taking to Truth Social to say that although the Court upheld birthright citizenship, the administration “can easily make it up in Congress through Legislation…No long and unwieldy Constitutional Amendment is necessary!” The president further urged Congress to “start today,” pledging his “complete and total support.” Contrary to the President’s assertion, five Justices held that birthright citizenship for children of undocumented or temporary parents is constitutionally protected by the Fourteenth Amendment, making this significantly more than a simple case of statutory interpretation. As such, even if Congress amended § 1401(a) along the lines of what Justice Kavanaugh’s opinion contemplates, the resulting law would still conflict with the Fourteenth Amendment, and would presumably bring on the same result as the President’s executive order.

However, the road to ending birthright citizenship is far rockier than the president’s post or even Justice Kavanaugh’s opinion might suggest. Setting aside the clear constitutional obstacle, passing a statute stripping children of undocumented or temporary immigrants of their citizenship status would require Congress to take a recorded and controversial vote on an issue that polls ambivalently across the country. To do so heading into the 2026 primaries, with Senate Republicans in swing states already wary of votes that may cost them their seats, would be nothing if not risky. An executive order enables a president to act unilaterally, meaning they absorb the brunt of the criticism and consequences in the polls; a statute change, however, spreads that exposure across each member who votes for it. And while Justice Kavanaugh’s opinion supplies a theoretical road map to execute the policy, whether Congress has the appetite for that path—in an election year—is a different question entirely.