Since joining the Supreme Court, Justices Neil Gorsuch and Brett Kavanaugh have signaled their desire to reconsider the non-delegation doctrine, a moribund principle of judicial review intended to police the limits of Congress’s ability to delegate its legislative functions. The non-delegation doctrine derives from Article I of the U.S. Constitution and traces its lineage to early 20th century jurisprudence, but it has been decades since the Supreme Court has used it to find an act of Congress or of the executive branch unconstitutional. Given its current makeup, the Court could break that streak as the Biden administration follows through with its September 2021 announcement and issues a vaccine mandate through the Occupational Safety and Health Administration.
There is little doubt federal courts will be called on to decide the constitutionality of the OSHA mandate, and any such case almost certainly would reach the Supreme Court. In addition to the merits of the question itself (i.e., whether OSHA has the statutory authority to issue a mandate and whether Congress has the ability to delegate that policy decision to OSHA in the first place), an intriguing aspect of the case would be how Gorsuch and Kavanaugh might frame the case. Given their stated desire to revisit non-delegation, such a case might be another vehicle to do just that. But it is not clear they would move to that position directly. In the past, both justices have invoked the major questions doctrine as their preferred path to application of non-delegation principles. Because, as Gorsuch wrote, “When one legal doctrine becomes unavailable to do its intended work, the hydraulic pressures of our constitutional system sometimes shift the responsibility to different doctrines.”
The major questions doctrine is generally understood to be a canon of statutory interpretation. Where a congressional grant of authority to an executive branch agency has significant economic and political repercussions, courts look for a “clear statement” of legislative intent. For example, in the recent CDC eviction moratorium case, where the Supreme Court held the moratorium was outside the agency’s authority, the Court explained that it “expect[s] Congress to speak clearly when authorizing an agency to exercise powers of vast economic and political significance,” which was lacking in that case. The Supreme Court also applied the major questions doctrine in UARG v. EPA to reject the agency’s new greenhouse gas emission standard. It reached that decision in part because the standard would have had a huge impact on the U.S. economy and the governing statute did not clearly grant the authority to act as the agency claimed:
When an agency claims to discover in a long-extant statute an unheralded power to regulate a significant portion of the American economy, we typically greet its announcement with a measure of skepticism. We expect Congress to speak clearly if it wishes to assign to an agency decisions of vast economic and political significance.
Instead of viewing the major questions doctrine primarily as a canon of statutory interpretation, however, Gorsuch and Kavanaugh have both indicated the doctrine is best seen as serving a non-delegation function. In his dissent in Gundy, Gorsuch, after describing the contours of the doctrine, explained that “[a]lthough it is nominally a canon of statutory construction, we apply the major questions doctrine in service of the constitutional rule that Congress may not divest itself of its legislative power by transferring that power to an executive agency.” Kavanaugh agrees. Writing in dissent as a circuit court judge, he stated “[t]he major rules doctrine helps preserve the separation of powers and operates as a vital check on expansive and aggressive assertions of executive authority.”
Perhaps the clearest statement of Justice Kavanaugh’s views on this matter, and an intimation of what a majority Supreme Court decision invalidating OSHA’s vaccine mandate might look like, occurs in his statement following the denial of certiorari in Paul v. United States. As he explained:
Justice Gorsuch’s scholarly analysis of the Constitution’s nondelegation doctrine in his Gundy dissent may warrant further consideration in future cases. Justice Gorsuch’s opinion built on views expressed by then-Justice Rehnquist some 40 years ago in Indusial Union Dept., AFL–CIO v. American Petroleum Institute, 448 U. S. 607, 685–686 (1980) (Rehnquist, J., concurring in judgment). In that case, Justice Rehnquist opined that major national policy decisions must be made by Congress and the President in the legislative process, not delegated by Congress to the Executive Branch.
In the wake of Justice Rehnquist’s opinion, the Court has not adopted a nondelegation principle for major questions. But the Court has applied a closely related statutory interpretation doctrine: In order for an executive or independent agency to exercise regulatory authority over a major policy question of great economic and political importance, Congress must either: (i) expressly and specifically decide the major policy question itself and delegate to the agency the authority to regulate and enforce; or (ii) expressly and specifically delegate to the agency the authority both to decide the major policy question and to regulate and enforce . . . .
The opinions of Justice Rehnquist and Justice Gorsuch would not allow that second category—congressional delegations to agencies of authority to decide major policy questions—even if Congress expressly and specifically delegates that authority. Under their approach, Congress could delegate to agencies the authority to decide less-major or fill-up-the-details decisions.
Like Justice Rehnquist’s opinion 40 years ago, Justice Gorsuch’s thoughtful Gundy opinion raised important points that may warrant further consideration in future cases.
In the case of OSHA’s vaccine mandate, courts likely will find the major questions doctrine applicable. The mandate implicates significant economic and political effects because of its nationwide scope and potential application to upwards of 100 million people. In addition, neither Congress nor OSHA nor any other federal agency, even those most directly involved with the control of infectious disease, has ever mandated a vaccine in this way. The mandate, in other words, would be unprecedented, affect the health care decisions and personal autonomy of millions of Americans, and have repercussions sounding throughout the U.S. economy.
Further, it is doubtful Congress unambiguously authorized OSHA to enact such a vaccine mandate. If the CDC eviction moratorium case is any indication, a majority of the Supreme Court will likely turn a skeptical eye on that position. OSHA’s governing statute does not directly speak to this issue and, in the past, OSHA’s authority has been exercised only to require employers to provide a safe workplace against toxic substances and dangerous physical conditions. It has never been used to mandate vaccines against a communicable disease circulating in the general population. OSHA also does not have expertise in infectious disease or in the efficacy of particular vaccines, nor does the statute contemplate OSHA developing that expertise. Congress has given that kind of regulatory authority/expertise to the Department of Health and Human Services instead. OSHA’s rule would thus be akin to the issue in UARG where the agency found within a “long-extant statute an unheralded power to regulate a significant portion of the American economy.” The Court frowns on such novel discoveries. Therefore, the Supreme Court may very well invalidate the OSHA vaccine mandate as failing to meet the requirements of the major questions doctrine.
Perhaps more importantly for future cases, if an OSHA vaccine mandate case does reach the Supreme Court and Gorsuch and Kavanaugh are able to influence a sufficient number of their colleagues, we might find a more robust assertion of non-delegation principles than we have seen in a very long time.
Lee A. Steven is senior policy counsel at Americans for Prosperity Foundation.
 See Gundy v. United States, 588 U.S. ___, ____; 139 S. Ct. 2116, 2131–48 (2019) (Gorsuch, J., dissenting); Paul v. United States, 589 U.S. ____ (2019) (statement of Kavanaugh, J.) (“I write separately because Justice Gorsuch’s scholarly analysis of the Constitution’s nondelegation doctrine in his Gundy dissent may warrant further consideration in future cases.”). Both Chief Justice Roberts and Justice Thomas joined Justice Gorsuch in his Gundy dissent.
 See A.L.A. Schechter Poultry Corp. v. United States, 295 U.S. 495, 529 (1935) (“The Constitution provides that ‘All legislative powers herein granted shall be vested in a Congress of the United States, which shall consist of a Senate and House of Representatives.’ Art I, § 1. And the Congress is authorized ‘To make all laws which shall be necessary and proper for carrying into execution’ its general powers. Art. I, 8, par. 18. The Congress is not permitted to abdicate or to transfer to others the essential legislative functions with which it is thus vested.”).
 See id.; Panama Refining Co. v. Ryan, 293 U.S. 388 (1935); see also Keith E. Whittington & Jason Iuliano, The Myth of the Nondelegation Doctrine, 165 U. Penn. L.R. 379 (2017); Stephen Wermiel, SCOTUS for law students: Non-delegation doctrine returns after long hiatus, SCOTUS Blog (Dec. 4, 2014), https://bit.ly/2YsUrSD.
 See, e.g., CBS News, Biden announces COVID-19 vaccine mandates that will affect 100 million Americans, https://cbsn.ws/3iKjF6b. (reporting on the administration’s intention to issue a mandate through OSHA that would apply to all employers with 100 or more employees and would require employees either to be vaccinated or tested for COVID-19 at least once a week).
 Numerous governors and state attorneys general declared their intention to challenge the mandate in court. See, e.g., Letter from State of Tennessee, Office of the Attorney General to President Biden (Sept. 16, 2021), https://bit.ly/3oLjA6a.
 Gundy, 139 S. Ct. at 2141 (Gorsuch J., dissenting).
 Alabama Ass’n of Relators v. HHS, 594 U. S. __, __ (2021) (slip op. at 6) (cleaned up).
 See also FDA v. Brown & Williamson Tobacco Corp., 529 U.S. 120, 133 (2000) (courts are to “be guided to a degree by common sense as to the manner in which Congress is likely to delegate a policy decision of [significant] economic and political magnitude to an administrative agency.”); Whitman v. American Trucking Ass’ns, 531 U.S. 457, 468 (2001) (“[The] textual commitment must be a clear one. Congress, we have held, does not alter the fundamental details of a regulatory scheme in vague terms or ancillary provisions—it does not, one might say, hide elephants in mouseholes.”).
 Utility Air Regulatory Group v. EPA, 573 U.S. 302, 324 (2014); see also United States Forest Service v. Cowpasture River Preservation Assn., 590 U. S. ___, ___ (2020) (slip op. at 15–16) (Supreme Court precedents “require Congress to enact exceedingly clear language if it wishes to significantly alter the balance between federal and state power and the power of the Government over private property.”).
 Gundy, 139 S. Ct. at 2141–42 (Gorsuch J., dissenting) (cleaned up) (“Under our precedents, an agency can fill in statutory gaps where statutory circumstances indicate that Congress meant to grant it such powers. But we don’t follow that rule when the statutory gap concerns a question of deep economic and political significance that is central to the statutory scheme.”).
 Id. at 2142.
 U.S. Telecom Ass’n v. FCC, 855 F.3d 381, 417 (2017) (Kavanaugh, J., dissenting).
 Paul, 589 U.S. at ____.
 See supra note 4.
 See, e.g.,42 U.S.C. § 247d (granting secretary of HHS certain authority to address public health emergencies, which is defined to include “significant outbreaks of infectious diseases”).
 UARG, 573 U.S. at 324.