Introduction
In December 2025, without oral argument or a written opinion, the Supreme Court did something it had never done before: It set aside a lower court judgment upholding a vaccine mandate that lacked religious exemptions. In Miller v. McDonald,1 the Court granted certiorari, vacated the Second Circuit’s decision, and remanded “for further consideration in light of Mahmoud v. Taylor,”2 its newest religious liberty ruling in which it held that public school policies substantially burden parents’ free exercise rights when they interfere with children’s religious development.3 That was the entirety of the Court’s reasoning.4 Yet the signal is difficult to ignore. A case about opt-outs from LGBTQ-inclusive storybooks is now the lens through which a lower court must consider public-health mandates.
By treating Mahmoud as relevant to a paradigmatic public-health mandate, the Court has invited constitutional exemptions not only from what children are taught, but also from what the state requires to keep them, and others, safe. Vaccine mandates have long served as the canonical limit case, the example the Supreme Court has consistently invoked to mark where religious liberty does not reach.5 If the Court is signaling that Mahmoud extends to vaccine mandates, it has quietly unsettled one of the most enduring premises of its free exercise jurisprudence.6
The Miller grant-vacate-remand (GVR) is, in that sense, a case study in how some GVRs function — not as routine housekeeping directing a lower court to apply clearly relevant intervening precedent,7 but as a mechanism for extending recent precedent into territory it did not address and that existing doctrine appears to foreclose. When a GVR points one way and the Court’s prior statements point another, the result is a forced choice. In Miller, the GVR leaves the lower court caught between the Court’s century of statements treating vaccines as the outer boundary of religious liberty and an order that unsettles that premise — a choice that risks error either way. That dilemma matters beyond Miller, illuminating how some GVRs do substantive doctrinal work without openly saying so.
This Essay proceeds in four Parts. Part I traces the doctrinal baseline, showing that vaccines have long functioned as the limit case for religious liberty. Part II briefly describes the doctrinal changes of the COVID-19 era — the Supreme Court’s expansion of religious equality doctrine, and its emergency-docket denials that left vaccine mandates formally unresolved — before explaining why the GVR in Miller signals a different move: the extension of the religious liberty framework to vaccine mandates, bypassing the comparability analysis that had allowed most courts to sustain them under the equality model. Part III turns to Miller itself and the Second Circuit’s decision upholding New York’s repeal of its religious exemption. Part IV returns to the Miller GVR as a window into the Court’s broader practice of communicating consequential legal directions through orders, and argues that the GVR is best understood as doing substantive doctrinal work by treating Mahmoud as bearing on vaccine mandates. In doing so, the GVR unsettles a century-old premise about religious liberty and children’s health and forces the lower court into an interpretive bind, given that the Court has not squarely repudiated the older baseline.
I. Background
Vaccines have served as the limiting case across every era of the Court’s free exercise jurisprudence, the example invoked to show that some exercises of state power are simply beyond religious liberty challenge. The doctrinal foundation is Jacobson v. Massachusetts,8 the 1905 decision in which the Supreme Court addressed a Cambridge ordinance requiring residents to be vaccinated against smallpox or pay a five-dollar fine.9 The Court held that “a community has the right to protect itself against an epidemic of disease which threatens the safety of its members.”10
For more than a century, Jacobson functioned as the Court’s leading infectious-disease decision and a principal authority for the constitutionality of vaccine mandates.11 Jacobson was not a free exercise case — it predated the incorporation of the Free Exercise Clause against the states by thirty-five years — but once free exercise was incorporated in 1940,12 Jacobson’s logic was absorbed into the Court’s understanding of free exercise’s boundaries.13
The Court made the point explicit in the child-welfare context in 1944,14 when it upheld a child-labor law against a Jehovah’s Witness guardian.15 The state’s authority over children’s welfare, the Court explained, “reaches beyond the scope of its authority over adults.”16 Pointedly, the Court observed that a parent “cannot claim freedom from compulsory vaccination for the child more than for himself on religious grounds. The right to practice religion freely does not include liberty to expose the community or the child to communicable disease or the latter to ill health or death.”17
That principle was reaffirmed in the Court’s two leading twentieth-century free exercise decisions recognizing constitutional protection for religious claimants against the state,18 and repeatedly elsewhere as well.19 Finally, in Employment Division v. Smith20 — the Court’s canonical 1990 decision — Justice Scalia, writing for the Court, specified “compulsory vaccination laws” as among those laws that obviously do not require religious exemptions,21 citing as an example a state supreme court decision holding that parents were not entitled to a religious exemption from a school vaccination requirement.22
In a word, the doctrinal line was clear for over a century: Religious liberty does not encompass the right to expose communities to communicable disease. Unsurprisingly, all courts to address a free exercise challenge to a vaccine mandate rejected it.23 Indeed, courts treated the suggestion that religious freedom could entitle one to opt out of a vaccine mandate as barely worthy of engagement,24 and some courts went further, striking down religious exemptions from vaccine mandates as unconstitutional given the health risks they impose on others.25
II. Vaccines and Free Exercise: Religious Equality vs. Liberty
Doctrinal change began during the COVID-19 pandemic. Following Justice Barrett’s confirmation in 2020, the Court significantly expanded the meaning of religious discrimination through two new rules. First, in Tandon v. Newsom,26 the Court held that heightened scrutiny applies whenever religiously motivated activity is treated less favorably than “comparable” secular activity, such that even a single secular exception to a law can trigger strict scrutiny of the denial of religious exceptions.27 Second, in Fulton v. City of Philadelphia,28 the Court established an “anti-discretion” rule: Whenever officials retain discretion to grant exemptions, refusing a religious exemption is presumptively unconstitutional even if officials have never granted an exemption for any reason.29 These principles led some lower federal courts to hold that governments must provide religious exemptions from vaccine mandates,30 though most courts resisted that conclusion.31
The Supreme Court, for its part, also stopped short of extending those principles to vaccine mandates. In late 2021, the Court declined to grant emergency relief in Does 1–3 v. Mills,32 a religious discrimination challenge to Maine’s healthcare worker vaccine mandate.33 The Court provided no explanation, but Justice Barrett, joined by Justice Kavanaugh, offered a procedural rationale: It is generally preferable to avoid granting such relief to prevent petitioners from using “the emergency docket to force the Court to give a merits preview . . . on a short fuse without benefit of full briefing and oral argument.”34 This rationale, however, sat uneasily with those same Justices’ willingness to grant emergency relief in other COVID-19 religious equality cases that raised the same procedural concerns.35 Justice Gorsuch, joined by Justices Thomas and Alito, wrote a strongly worded dissent.36 The Court again denied emergency relief in another vaccine mandate case, Dr. A. v. Hochul,37 a few months later; Justice Gorsuch, joined by Justice Alito, again wrote a dissenting opinion.38 The Court denied certiorari in several similar challenges, with Justices Thomas, Alito, and Gorsuch dissenting from at least one denial.39
The GVR in Miller v. McDonald — involving a religious liberty challenge to a childhood vaccine mandate — marks the first time the Court has addressed vaccine mandates since those COVID-19 denials.40 This time, a majority of the Court was willing to vacate a lower court decision upholding a vaccine mandate without religious exemptions. What explains the shift? The answer likely lies in the difference between the religious equality logic the Court developed during COVID-19 and the religious liberty rule Mahmoud established. The pandemic-era cases focused on whether secular and religious exemptions are comparable, a question most courts answered in the state’s favor.41 Mahmoud, by contrast, asks only whether the mandate substantially interferes with a child’s religious upbringing.42
In Mahmoud, several religious parents challenged their school district’s policy of not granting opt-outs from instruction involving LGBTQ-inclusive storybooks for students in prekindergarten through fifth grade.43 They argued that the picture books conveyed normative views about same-sex marriage and gender identity contrary to their religious beliefs.44 In a 6–3 decision authored by Justice Alito, the Court held that the school district’s refusal to provide opt-outs substantially burdened the parents’ free exercise rights by interfering with their ability to direct the religious upbringing of their children.45 Relying heavily on Wisconsin v. Yoder,46 the Court’s 1972 decision exempting Amish families in Wisconsin from compulsory high school attendance,47 the Court concluded that government policies that “substantially interfer[e] with the religious development” of children trigger strict scrutiny, even when those policies are neutral and generally applicable.48
The significance of that framework for vaccine mandates lies in what it sidesteps. Under the Court’s recent religious equality rule, heightened scrutiny is triggered whenever the government permits secular conduct that undermines its asserted interest to the same or greater degree as would the religious conduct it burdens.49 That rule has incentivized courts to define the government’s interest at the level of generality most likely to yield their preferred outcome, particularly in the vaccine context.50 Most courts addressing vaccine mandates have reasoned that while a religious exemption would undermine the state’s interest in “public health” — understood at a high level of generality rather than in more granular terms, such as immunizing the populace against a specific disease — existing medical exemptions, in fact, advance it.51
Religious liberty is, in that respect, a cleaner vehicle.52 It requires only a showing that the claimant holds a sincere religious belief that prevents compliance with the law, after which the state must satisfy strict scrutiny.53 The same feature that likely explains the Court’s shift, that liberty bypasses the comparability thicket, also makes the move more consequential. A right that does not depend on comparative treatment is a right that is harder to resist.
In earlier work, I observed that while “courts operating under the liberty model”54 had not been “willing to even entertain the notion that free exercise includes entitlement to an exemption from a vaccine mandate,”55 the structure and rhetoric of religious equality allowed courts to venture where it was previously considered anathema to go.56 In Miller, the Court appears to be taking a step neither it nor any known court in American history has taken: extending religious liberty to vaccine mandates when the objection involves vaccines administered to children — an inversion of Prince v. Massachusetts’s57 foundational premise that the state’s authority over children rests on stronger constitutional footing than its authority over adults.58 On that view, the presence of children no longer weakens the claim for a religious exemption; it strengthens it. The Court’s choice of a GVR rather than a merits decision, however, suggests some continuing hesitation about saying so outright.
III. Miller v. McDonald
Miller v. McDonald concerns New York’s 2019 decision, following a severe measles outbreak, to remove religious exemptions from its school vaccination requirement.59 The outbreak was the worst in the United States in nearly three decades.60 Nearly a thousand cases were confirmed in New York alone,61 concentrated in communities where vaccination rates had fallen dangerously low.62 Dozens were hospitalized.63 Twenty were admitted to intensive care.64 The outbreak threatened the nation’s measles elimination status.65 The state legislature responded by repealing its religious exemption, which had driven the sharp decline in vaccination.66 Three Amish schools were fined approximately $120,000 for allowing unvaccinated children to attend.67
The schools and several parents challenged the law under the Free Exercise Clause.68 They cast the case in Yoder’s terms: The mandate, they said, forced Amish parents to choose between vaccinating their children against their religious beliefs and abandoning communal schooling,69 which they described as a “vital part” of their children’s spiritual development.70
The Second Circuit rejected the challenge.71 The court carefully engaged the precedents, with Yoder foremost among them, that Mahmoud would later rely on.72 It concluded that Yoder did not apply because the risk to free exercise posed by vaccination requirements was “not equivalent to the existential threat the Amish faced in Yoder.”73 The vaccination mandate did not imperil the continued survival of the Amish community in the way that compulsory high school attendance did.74
The court also stressed the public health limitation that Yoder itself recognized.75 It emphasized that Yoder was “limited by the state’s interest in protecting public health,” pointing to what Yoder described as Prince’s “apparently uncontroversial proposition that a parent ‘cannot claim freedom from compulsory vaccination for the child more than for himself on religious grounds’ because the ‘right to practice religion freely does not include liberty to expose the community or the child to communicable disease.’”76 And it underscored Yoder’s own assurance that the exemption there would not cause “harm to the physical or mental health of the child,” an assurance exemptions from vaccination mandates could not possibly offer.77
But on December 8, 2025, without oral argument or a written opinion, the Court granted the plaintiffs’ petition, vacated the Second Circuit’s judgment, and remanded “for further consideration in light of Mahmoud v. Taylor.”78
IV. What’s in a GVR?
That GVR makes Miller a case study in a broader phenomenon. The Court has increasingly communicated consequential legal signals to lower courts through orders that lack the reasoning those courts need to implement them. The dynamic is especially acute on the emergency docket, where the Court has resolved high-stakes disputes through emergency orders — often without majority opinions and sometimes without any explanation at all — while leaving lower courts to decide what weight to give those orders.79 Recent commentary has described this as the lower courts’ “foreshadow” problem: When the Court’s orders signal a doctrinal shift without changing the law on the merits, lower courts face the task of deciding whether to adhere to existing doctrine or anticipate where the Court is heading.80
Yet a GVR like Miller poses a harder version of the problem. The order does not merely signal a future doctrinal direction. It vacates a judgment and directs reconsideration in light of a decision that does not obviously apply, thereby communicating something substantive about that decision’s scope.81 The lower court must decide how to respond to that communication, though it lacks guidance about what, exactly, must change — and though, as in Miller, the GVR’s implicit instruction cuts against the Court’s own earlier pronouncements.82
The costs of this practice have become impossible to ignore. Recently, Justice Gorsuch, joined by Justice Kavanaugh, admonished district judges for failing to follow a prior emergency ruling: “Lower court judges may sometimes disagree with this Court’s decisions, but they are never free to defy them.”83 The targeted judge publicly apologized, explaining that he “simply did not understand that orders on the emergency docket were precedent.”84 But a different district judge offered a more pointed response:
[I]t is unhelpful and unnecessary to criticize district courts for “defy[ing]” the Supreme Court when they are working to find the right answer in a rapidly evolving doctrinal landscape, where they must grapple with both existing precedent and interim guidance from the Supreme Court that appears to set that precedent aside without much explanation or consensus.85
Granted, Miller is not quite the same as these interim orders. The intervening precedent, Mahmoud v. Taylor, is a merits decision, decided after full briefing and oral argument, with a majority opinion spanning several dozen pages. Yet the Second Circuit received no guidance on how that opinion applies to vaccine mandates, a context Mahmoud did not address and that much of its reasoning appears to exclude.86 Often, the instruction is obvious — the Court has just replaced one test with another, and the GVR directs the lower court to apply it.87 Here, the instruction to issue a new decision “in light of Mahmoud”88 demands more deduction, if not divination, from the court of appeals.
The difficulty is that Mahmoud lends itself to a narrow construction — one most lower courts have adopted89 — that confines it to a specific curricular context and education’s distinctive capacity to shape children’s religious development, though the opinion’s language also sweeps more broadly.90 Under the narrow reading, Mahmoud’s central holding does not apply to vaccine mandates. But even under a more expansive construction that extends Mahmoud beyond the curriculum — one the Court appears to have embraced in a subsequent emergency order regarding a public school student pronoun policy91 — the question remains whether Mahmoud extends to vaccines, which for over a century have been treated as beyond the reach of liberty challenges.92
* * *
A grant-vacate-remand order, to be sure, is not a holding. But neither is it empty.93 The Court has explained that a GVR is appropriate only when intervening developments “reveal a reasonable probability that the decision below rests upon a premise that the lower court would reject if given the opportunity for further consideration, and where it appears that such a redetermination may determine the ultimate outcome of the litigation.”94 Vacatur is costly: It wipes out a judgment, imposes delay, and consumes lower court resources. The Court’s own teaching is that this power should be used “sparingly.”95 The point is not that one should read meaning into a GVR that is not there.96 It is that the lower court cannot now proceed as if nothing happened.
The question, then, is what the Miller GVR demands the lower court do differently. The answer requires working through the possible readings of the order — asking what, exactly, justified the vacatur. The most natural reading is that the lower court must now apply Mahmoud to the vaccine mandate.97 That means treating Mahmoud’s core holding as applicable here and recognizing a presumptive parental right to exemptions from challenged requirements whenever they interfere with raising one’s children in accordance with one’s religious beliefs.98 The alternative is that the Second Circuit erred by treating Wisconsin v. Yoder as inapplicable.99 But that yields the same result, because to apply Yoder as it has been reconstructed by the Court in Mahmoud means that parents have the same presumptive right.
One might imagine a narrower possibility: that the Second Circuit was right to find Yoder inapplicable, but it did so for the wrong reason. It should not have limited Yoder’s applicability to cases involving the preservation of a vulnerable religious community100 — a fact-bound narrowing that Mahmoud rejected — though it could have distinguished Yoder on other grounds, such as that education, unlike vaccination mandates, uniquely implicates Yoder’s parental religious-upbringing right as Mahmoud construed it.
The problem is that the Second Circuit said exactly that and devoted ample space to explaining how Yoder is distinguishable on precisely that ground: It involved education, which is categorically different from vaccination mandates rooted in public health.101 The court explained that “Yoder’s holding is limited by the state’s interest in protecting public health,”102 and emphasized that the Yoder Court “specifically distinguished the facts from Prince v. Massachusetts,”103 in which the Court had declared that the “right to practice religion freely does not include liberty to expose the community or the child to communicable disease or the latter to ill health or death.”104
And even if the Second Circuit erred in distinguishing Yoder for the wrong reason, it would be harmless error in its purest form — an error that could not possibly have changed the outcome. It would mean that if the Second Circuit had added a single sentence noting that vaccines are not curriculum — which it in fact did in spades — the Supreme Court would have denied certiorari. On that account, to rectify matters, the court of appeals could now simply add a footnote. A vacatur that forces a full redo is a strange instrument for so small a correction.
What remains is the only reading that makes the vacatur intelligible: The Court is signaling that Mahmoud’s “Yoder exception”105 extends beyond the curricular context. On that view, whenever the burden is “of the same character” as in Yoder, strict scrutiny applies irrespective of neutrality and general applicability.106 And that “character” is defined in terms not limited to education. It refers to any policy that “substantially interfer[es] with the [child’s] religious development,” regardless of context.107 Here, that would mean that parents have a presumptive right to refuse vaccines for their children when compliance interferes with their ability to raise them according to their religious beliefs.108 And of course it does. It is hard to teach children the religious value of refusing vaccination while injecting them with vaccines.109
One might object that I am reading too much into a GVR — that it signals nothing more than that the Court is undecided or prefers lower courts to take the first pass before weighing in itself.110 That may be so as a general matter. But not all GVRs are alike, and Miller is a case in point. The lower court cannot now simply repeat its previous analysis, this time appending a line stating merely that “we have considered the intervening Supreme Court decision.” On remand, it must determine what in the new decision requires it to alter its previous reasoning. Usually, this is straightforward: The Court has replaced one test with another, and the lower court must apply the new one. But when the Court’s new decision is not obviously applicable — as it was not in Miller111 — the very fact that the Court has informed the lower court that the decision bears on its case carries independent substantive weight. The lower court is not free to shrug and say, “Nope, it doesn’t.” If that is right, the Miller GVR is communicating something significant about how the Court understands the scope of the right it recognized in Mahmoud.112
That Mahmoud’s reach extends beyond the curricular context is no longer speculative. A few months after Miller, the Court took another step in Mirabelli v. Bonta.113 In an emergency order, it vacated a Ninth Circuit stay and thereby reinstated a district court injunction against a California school policy requiring educators to use students’ preferred names and pronouns while withholding from parents information about students’ social transition.114 The Court invoked Mahmoud. The case did not involve storybooks, lessons, or anything that looked like classroom pedagogy. Even so, Mahmoud was treated as controlling.115
Still, lower courts’ narrow reading of Mahmoud is neither surprising nor unreasonable. Mahmoud itself was a study in deliberate ambiguity — it announced a broad right in sweeping language while emphasizing factual details that seemed to cabin it, leaving lower courts toguess which signal to follow.116 When the Ninth Circuit in Mirabelli, like nearly all other lower courts,117 read the ambiguity as narrowing — confining Mahmoud to the curricular context — the Court responded not so much by clarifying as by chastising, using an emergency order to declare that the court of appeals had problematically “brushed aside Mahmoud” by treating the decision as overly “narrow.”118
Vaccine mandates, though, have long stood apart. The Court has stated repeatedly that religious liberty does not include a right to refuse vaccination.119 By treating Mahmoud as transferable in Miller, the Court has unsettled that premise without saying so directly, leaving it unclear whether the vaccine limitation still holds. The result is a genuine bind for the lower court. The Supreme Court’s accumulated statements point one way; the order points the other. The lower court must decide whether to adhere to those statements or to read the order as signaling that they have been superseded.120
One response to that bind is to return the favor. If the Supreme Court is going to communicate significant doctrinal views through unexplained orders — a form of cryptic (and false) minimalism121 — the court of appeals can decline to take the hint, forcing the Court to do the radical work itself rather than delegating it to lower courts.122 The court would be well within its rights to hold the Supreme Court to its own repeated statements, and treat the vaccine limitation as intact, until it explicitly repudiates them.123 That would not constitute “defy[ing]”124 the Supreme Court so much as faithfully following the Court’s own prior instructions.125
The alternative, as discussed, is to read the GVR as communicating what its logic most plausibly implies — that parents have a presumptive right to refuse vaccination on religious grounds, triggering strict scrutiny. To survive that test, the state would need to prove that denying religious exemptions is necessary to fulfill its compelling interests, a showing that would be difficult under the Court’s recent free exercise strict scrutiny jurisprudence. The mere fact that the state does offer some exemptions, just not religious ones, undermines its claim that it is impossible to provide a religious exemption — that is, that the law “brook[s] no departures”126 whatsoever, the standard the Court has required.127 If strict scrutiny operates here as it has for the Court in free exercise cases in recent years — as a practically insurmountable bar — the recognition of a presumptive right virtually guarantees its vindication.128
And regardless of the mandate’s ultimate outcome, the Miller GVR has already transformed the constitutional status of vaccination requirements from a self-evident limit on religious liberty to a question within it.
Conclusion
Miller is a case study in how some GVRs extend doctrine by implication. The Court used a GVR to signal that its newest religious liberty decision bears on a context that the decision did not address and that a century of authority appeared to foreclose — not through a holding, but by vacating a judgment and invoking a precedent that does not obviously govern. In doing so, it unsettled what was long treated as one of the Court’s clearest constitutional baselines: that the state’s authority to protect children and the community from communicable disease marks the outer boundary of religious liberty, not an occasion for its vindication. For more than a century — from Jacobson to Prince to Smith — that baseline kept vaccination requirements out of the exemption machinery, treating them instead as a paradigmatic exercise of the police power. The Miller GVR unsettles that premise without squarely repudiating it, leaving lower courts to choose between two forms of error: performing the work of doctrinal revolution in the Court’s stead, or adhering to precedent the Court has arguably already displaced, thereby risking the charge of “defy[ing]” the Court’s remand.129 Either choice breeds instability in an area where lives depend on legal certainty. If the Court is prepared to rethink the constitutional status of vaccination mandates, it should say so explicitly — and bear the consequences.