Are Trump’s Tariffs Legal?

Most of the president’s emergency powers derive from statutes rather than directly from the Constitution. And those powers can be sweeping. They enable the president to respond to emergencies that may include financial panics, natural disasters, contagious diseases, terrorist attacks, disruptions in energy supplies, labor strikes, or shortages of materials essential for the national defense. Such delegations are constrained, however, by an overarching separation of powers principle: that while Congress may delegate much of its power, it may not delegate the law-making power itself.

Interpreting that constraint has bedeviled constitutional jurisprudence for two centuries. In Wayman v. Southard (1825), Chief Justice John Marshall ruled that while Congress may not delegate powers that are “strictly and exclusively legislative,” “[t]he line has not been exactly drawn which separates those important subjects which must be entirely regulated by the legislature itself from those of less interest in which a general provision may be made and power given to those who are to act under such general provisions to fill up the details.” But drawing that line “exactly” has proven difficult.

In general, the Supreme Court has long maintained that if Congress provides the executive with an “intelligible principle” to guide its implementation of the policy of a statute, the delegation is permissible. In the leading case J.W. Hampton, Jr. & Co. (1928), the Court stated: “If Congress shall lay down by legislative act an intelligible principle to which the person or body authorized to fix such [tariff] rates is directed to conform, such legislative action is not a forbidden delegation of legislative power.” Over most of the past century, the Court has interpreted the “intelligible principle” standard in an extremely broad and accommodating way, and Congress has responded by delegating extensive powers on the executive, even in such core areas of congressional power as taxation or criminal law. However, the Court has also insisted that there are some limits to delegation: e.g., Congress may not empower an agency “to regulate the entire economy on the basis of no more precise a standard than” assuring “‘fair competition.’” American Trucking Assn’s (2001). 

In recent decisions, the Court has sought to define the limits of delegation more clearly by invoking the “major questions doctrine.” This, it must be emphasized, is not itself a constitutional rule. Rather, it is a rule of statutory construction, albeit with constitutional underpinnings. Several of these cases arose during the COVID-19 public health emergency. For example, the Court temporarily blocked the Occupational Safety & Health Administration’s national Emergency Temporary Standard that mandated that employers with at least 100 employees implement mandatory vaccination programs for those employees or opt for a weekly testing alternative. The challenged OSHA Standard was “no everyday exercise of federal power” but “a significant encroachment into the lives – and health – of a vast number of employees.” Since the statute under which OSHA acted authorized it to regulate occupational and workplace hazards but not public health in general, OSHA’s Standard fell foul of the major questions doctrine. 

The pending case of Federal Communications Comm’n v. Consumers’ Research poses a more fundamental challenge to the Court’s broadly permissive approach to congressional delegations and might result in a stiffer understanding of the “intelligible principle” test.

Under the Court’s longstanding jurisprudence, however, there has been an important distinction between delegations of Congress’ authority over purely domestic matters and delegations that concern foreign policy, military or national security, immigration, and foreign trade. The executive possesses some measure of independent constitutional authority in all the latter areas. For example, Article II of the Constitution gives the president the “lead role in foreign policy” (Garamendi (2003)). When Congress “pools” its constitutional powers with the independent constitutional powers of the president, the courts treat the delegation with great deference. Chicago & S. Air Lines v. Waterman S.S. Corp. (1948).  Consequently, the Supreme Court has consistently rejected nondelegation challenges to statutes that empower the President to exercise sweeping discretion in foreign affairs, including foreign commerce. Curtiss-Wright Export Corp. (1936).

The Supreme Court elaborated on this theme in Kennedy v. Loving (1996), where it affirmed the authority of the president under a congressional delegation to prescribe aggravating factors for capital punishment in the military. It said (quotation marks omitted):

The President's duties as Commander in Chief, however, require him to take responsible and continuing action to superintend the military, including the courts-martial. The delegated duty, then, is interlinked with duties already assigned to the President by express terms of the Constitution, and the same limitations on delegation do not apply where the entity exercising the delegated authority itself possesses independent authority over the subject matter.

Likewise, the Court rejected a nondelegation challenge to the president’s authority to impose international travel controls in Zemel v. Rusk (1965):

because of the changeable and explosive nature of contemporary international relations, and the fact that the Executive is immediately privy to information which cannot be swiftly presented to, evaluated by, and acted upon by the legislature, Congress — in giving the Executive authority over matters of foreign affairs — must of necessity paint with a brush broader than that it customarily wields in domestic areas.

And because Congress’s power to regulate foreign commerce is closely intertwined with the president’s constitutional powers to conduct diplomacy, manage foreign relations, and protect national security, the Court has consistently upheld very large grants of congressional power over foreign commerce to the president.  E.g., in Algonquin SNG, Inc. (1976), the Court validated presidential restrictions on oil imports based on the very broad congressional language that delegated apparently unlimited regulatory authority to the executive branch.

Whatever the limits on Congress’s power to delegate its authority over domestic policy may be – and whatever the scope of the “major questions doctrine” – those questions must play out differently in the context of foreign affairs and foreign commerce. Indeed, the major questions doctrine may not apply in that context. And that seems particularly true when the legislation empowers the president to act in emergencies of foreign origin. Given the institutional attributes of the executive – its ability to act with energy, secrecy and dispatch, its access to many sources of information and analysis both at home and abroad, its control of the military, the intelligence and financial agencies and the diplomatic service, and its capacity to monitor and respond to rapidly changing events – Congress is warranted in conferring unusually broad powers to act on it. The courts should be expected to be extraordinarily deferential to the political branches’ choices. 

Trump’s Tariffs

President Trump has issued a series of executive orders that impose tariffs on imports from foreign nations – effectively, all of the United States’ global trading partners. The most sweeping of these orders, Regulating Imports with A Reciprocal Tariff to Rectify Trade Practices that Contribute to Large and Persistent Annual United States Goods Trade Deficits – was issued on April 2. Other orders were specifically addressed to the synthetic opioid supply chain in China. In issuing these orders, the president acted at the intersection of his Article II authorities regarding foreign affairs and national security and Congress’s authority to regulate foreign commerce. All relevant orders accordingly relied on statutory authority, principally the International Emergency Economic Powers Act, 50 USC 1701 et seq. (IEEPA). Do the orders exceed that authority?

IEEPA authorizes the president “to deal with any unusual and extraordinary threat, which has its source in whole or substantial part outside the United States, to the national security, foreign policy, or economy of the United States, if the president declares a national emergency with respect to such threat.” Among other authorities granted if those predicate conditions are met, the president “may, under such regulations as he may prescribe, by means of instructions, licenses, or otherwise— …  regulate, direct and compel, nullify, void, prevent or prohibit, any acquisition, holding, withholding, use, transfer, withdrawal, transportation, importation or exportation of, or dealing in, or exercising any right, power, or privilege with respect to, or transactions involving, any property in which any foreign country or a national thereof has any interest by any person, or with respect to any property, subject to the jurisdiction of the United States” (emphasis added). 

The analysis of the legality of Trump’s tariffs includes three steps:

1.   Are the predicate conditions satisfied?

2.  Are tariffs among the measures the president is authorized to take if the predicate conditions exist?

3.  Are the measures Trump has ordered reasonably related to the threat or threats to which the orders are addressed?

Do the Predicate Conditions Exist?

Do Trump’s orders identify an “unusual and extraordinary threat” of foreign origin to “the national security, foreign policy, or economy of the United States”? (Plainly, the other predicate – a presidential declaration of emergency – has been met.) 

The orders narrate at considerable length and in great detail the threats in question and their causes. The April 2 order, e.g., explains that “[l]arge and persistent annual U.S. goods trade deficits have led to the hollowing out of our manufacturing base; inhibited our ability to scale advanced domestic manufacturing capacity; undermined critical supply chains; and rendered our defense-industrial base dependent on foreign adversaries.” Elsewhere the order emphasizes the damaging effects on national security caused by the decline in our manufacturing capacity, which it in turn attributes to “the persistent decline in U.S. manufacturing output” said to be due to “the large and persistent annual U.S. goods trade deficit.” Increased reliance on foreign producers “also has compromised U.S. economic security by rendering U.S. supply chains vulnerable to geopolitical disruption and supply shocks,” as “was exposed during the COVID-19 pandemic, when Americans had difficulty accessing essential products.”

The orders that concern China in particular focus on the PRC’s support for “PRC-origin transnational criminal organizations (TCOs) that launder the revenues from the production, shipment, and sale of illicit synthetic opioids” such as fentanyl. “The influx of these drugs to our Nation threatens the fabric of our society. The PRC plays a central role in this challenge.”

Do the orders set forth an “unusual and extraordinary threat” to American “national security, foreign policy, or economy”? Opinions are sharply divided on that question. Critics of the April 2 order, e.g., reasonably question whether long-term trends in international trade that have been going on for half a century can be described as creating an “unusual and extraordinary threat.” Moreover, the order encompasses virtually all of our trading partners. But can persistent imbalances in our trade with, say, Lesotho or even Vietnam, really be said to be contributing to such a threat? And why should trading partners with which we usually maintain favorable trade balances be included?

Furthermore, it can be argued that emergencies are, by their nature, both unexpected and of short duration. Indeed, the House report on IEEPA stated, “emergencies are by their nature rare and brief, and are not to be equated with normal, ongoing problems.”   But the US trade imbalances are, as Trump’s orders explain, a longstanding problem that has unfolded over decades and that has arisen from the deep structure of international trading patterns.  Imbalances are neither “rare” nor “brief,” but rather “normal, ongoing problems.” 

Conversely, presidential practice has differed sharply from that restrictive interpretation. The Congressional Research Service (CRS) reported in 2024 that “on average, emergencies invoking IEEPA last more than nine years. The longest emergency was also the first. President Jimmy Carter, in response to the Iranian hostage crisis of 1979, declared the first national emergency under the provisions of the National Emergencies Act and invoked IEEPA. Seven successive presidents have renewed that emergency annually for more than 40 years.” Moreover, “the length of emergencies invoking IEEPA has increased each decade. The average length of an emergency invoking IEEPA declared in the 1980s was four years. That average extended to 11 years for emergencies declared in the 1990s and 15 years for emergencies declared in the 2000s.” 

Whether such objections and defenses are valid or not, they are misplaced. The relevant question is whether the President’s declaration of an emergency is a non-justiciable, “political” question. I think the courts would hold that it is.

In general, a presidential determination that an emergency has arisen when a statute delegates certain powers to him if that condition is found to exist is not within the judiciary's competence to reject. To take a related matter, the Supreme Court has recently reaffirmed its 1948 decision that the determination that a war has ended is a political question that precludes judicial review. Trump v. J.G.G. (April 7, 2025). And this is true of emergencies that arise under statutes regulating foreign trade. 

In US v. Yoshida International, Inc. (1975), the Court of Customs and Patent Appeals addressed the constitutionality of a temporary import duty surcharge that the president had imposed pursuant to the emergency powers delegated him by the Trading with the Enemy Act (TWEA). The court first found that the TWEA did, in fact, permit the president to impose the challenged import duty because its “plain and unambiguous wording” accorded him the power to “regulate importation” in the event of war or national emergency. As to the presidential finding that an emergency existed, it concluded that “courts will not normally review the essentially political questions surrounding the declaration or continuance of a national emergency.” Buttressing that conclusion, the court observed that “[o]f the three branches of government, only the Executive has a continuing, spontaneous capability for mounting [an emergency] response.” 

Moreover, even if the basis for the president’s declaration of an emergency is considered justiciable, it is still entitled to great deference from reviewing courts. Thus, in Trump v. Hawaii (2018), when reviewing President Trump’s ban on the entrance of persons from certain predominantly Muslim countries (a matter that the Court assumed, but did not decide, was justiciable), the Court said (quotation marks and citations omitted):

plaintiffs’ request for a searching inquiry into the persuasiveness of the President’s justifications is inconsistent with the broad statutory text and the deference traditionally accorded the President in this sphere. Whether the President’s chosen method” of addressing perceived risks is justified from a policy perspective is irrelevant to the scope of his [statutory)] authority. 

Does IEEPA Authorize Tariffs?

IEEPA does not, in terms, authorize the president to impose “tariffs” in response to a declared emergency. That does not matter, however. The statute plainly authorizes the president to “regulate, … prevent or prohibit, any acquisition, holding, withholding, use, transfer, withdrawal, transportation, importation or exportation, or dealing in, or exercising any right, power, or privilege with respect to, or transactions involving” covered property (emphasis added).  The reference to the powers to “regulate” and “prevent” “importation” of foreign goods is quite sufficient to justify the president in imposing tariffs.  

“Tariffs” are a means to “regulate” the “importation” of foreign goods into a country. (One legal source describes tariffs as “a tool of public law …  [They are] state-imposed levies, aimed at achieving public policy objectives. These objectives often encompass revenue generation, economic protectionism, and the regulation of foreign trade (emphasis added). The Legal Essence of Tariffs - The Law To Know ). Indeed, if sufficiently high, they may also “prevent or prohibit” such “importation.” The statutory reference to “transportation,” a term adjacent to “importation or exportation,” also suggests that the powers granted extend to covered items moved across international boundaries. 

In Yoshida, the court held that the very similar language of the TWEA undoubtedly permitted the imposition of import duties,that is, tariffs. Since IEEPA derives from TWEA (as the Supreme Court noted in Dames & Moore (1981)), and since Yoshida, a then-recent case, was presumably known to Congress when it enacted IEEPA in 1977, IEEPA should be construed to include the power to levy import duties/tariffs among the instrumentalities available to the president to respond to emergencies.

Trump’s use of IEEPA to impose tariff duties is unprecedented. Yet, as the CRS noted in 2024, while “[n]o President has used IEEPA to place tariffs on imported products from a specific country or on products imported to the United States in general…, IEEPA's similarity to TWEA, coupled with its relatively frequent use to ban imports and exports, suggests that such an action could happen.”   

Are Trump’s Tariffs Reasonably Related to the Threats He Identified?

The Yoshida court affirmed that although the courts may not review a presidential finding that an emergency exists, they may “review his acts arising from that judgment.” That is, the courts may inquire into “the extent to which the action taken bears a reasonable relation to the power delegated and to the emergency giving rise to the action.” 

On this question, Trump’s tariffs — or some of their applications of them might possibly fail. Arguably, the April 2 order is an attempt to usurp the entirety of Congress’s authority to determine the tariff policy of the United States. Even if, as I have suggested, the major questions doctrine does not apply to delegations of foreign policy powers, the more fundamental question is whether Congress can constitutionally delegate away the whole of its power to regulate foreign commerce (if that is what it has done).  

Against this, it can be argued that the gravity of the threats created by persisting trade imbalances is so severe that nothing short of a measure to cure that problem comprehensively would be sufficient. Moreover, some nations with which we have huge trade imbalances circumvent tariffs by offshoring production to nations left unsanctioned by Trump’s tariffs. (The Wall Street Journal has called China’s offshoring of manufacturing capacity to Mexico a “tariff-dodging” move.  To prevent this, it might be necessary to impose tariffs even on nations with which we do not run trade deficits. 

These questions cannot be answered before litigation creates a fuller record. And Trump might withdraw the April 2 tariffs and instead target a smaller selection of countries or imports, thus weakening the non-delegation argument. Time will tell.

Robert Delahunty is a Washington Fellow of the Claremont Institute Center for the American Way of Life in Washington DC.