Veteran constitutional lawyer Neal Katyal has sharply questioned President Donald Trump’s authority to impose a 15 per cent global tariff without explicit legislative backing, as the White House pushes ahead with controversial trade measures amid deep legal and political fault-lines. Katyal’s comments come as Mr Trump declared the higher tariff rate after the Supreme Court invalidated much of his previous tariff programme, triggering a constitutional battle over executive power and congressional prerogative. At the heart of the dispute is whether the president can unilaterally levy broad tariffs on imports — effectively functioning as taxes — without clear authorisation from Congress. The Supreme Court’s 6-3 ruling held that Mr Trump had overstepped his authority under the International Emergency Economic Powers Act, a statute originally designed for emergency responses, and underscored that taxation powers lie mainly with the legislature. The decision was authored by Chief Justice John Roberts, with a majority including both conservative and liberal justices.
Undeterred, Mr Trump swiftly pivoted to invoke Section 122 of the Trade Act of 1974, a rarely used statute that permits a temporary tariff of up to 15 per cent for 150 days without congressional approval. This shifted legal strategy has drawn immediate scrutiny from constitutional experts and figures such as Katyal, who highlighted inconsistencies in the administration’s legal rhetoric and the earlier position of the Justice Department. “It seems hard for the President to rely on the 15 per cent statute when his DOJ in our case told the court the opposite,” Katyal wrote on social media platform X, underscoring the contested legal ground on which the new tariffs rest.
Katyal’s broader argument is rooted in the foundational principle of separation of powers. He has long contended that tariffs constitute a form of taxation, and as such, only Congress — under Article I of the US Constitution — can authorise them. This was a key point in the case Learning Resources, Inc. v. Trump, in which the Supreme Court ruled that using the 1977 International Emergency Economic Powers Act to impose broad tariffs was unconstitutional. The majority opinion explicitly stated that the act did not grant the executive branch such sweeping authority, a ruling that has resonated in legal circles as a significant affirmation of legislative supremacy on taxation.
Katyal, a former Acting Solicitor General of the United States and a seasoned Supreme Court litigator, led the legal challenge on behalf of a coalition of small businesses and trade associations. He has described the court’s ruling as a reaffirmation of constitutional safeguards and the rule of law, asserting that presidents should not bypass Congress even for policies they view as beneficial. Outside the court, he has said that if a president believes a tariff is a good idea, he must work through the constitutional process to secure legislative approval.
Mr Trump’s response has been confrontational. After the court struck down his tariff actions, he criticised justices by name and accused the judiciary of undermining national interests, while reaffirming his commitment to pursuing trade measures he argues are necessary to rectify what he calls unfair global trade practices. Mr Trump’s supporters within his party’s populist wing have rallied behind his stance, viewing tariffs as essential to protecting domestic industries. Yet some Republican lawmakers have expressed unease with the legal strategy and economic implications, reflecting fissures within the party.
Economic analysts have pointed out that the shift to Section 122 is untested terrain, with potential for further litigation as its use confronts constitutional questions similar to those at the centre of the Supreme Court’s decision. Critics argue that tariffs, irrespective of how they are justified legally, ultimately raise costs for American consumers and disrupt global supply chains, complicating an already fragile economic landscape. Proponents counter that tariffs can serve as leverage in international negotiations, particularly with major trade partners.
The debate comes against a backdrop of wider political tensions over executive authority and legislative oversight. Constitutional scholars note that the clash highlights enduring questions about the balance of power in America’s federal system, especially as presidents face pressures to act swiftly on complex economic challenges. Katyal’s stance, rooted in decades of Supreme Court advocacy, embodies a school of thought that privileges legislative deliberation for decisions with broad fiscal impact.