Landmark IEEPA Lawsuit Questions President's Authority to Enact Wide-Ranging Tariffs

The U.S. Supreme Court is scheduled to hear oral arguments on November 5 in a pivotal case that will examine President Donald Trump's power to enact broad tariffs under the International Emergency Economic Powers Act (IEEPA) of 1977, as reported by

. Should Trump choose to attend, he would make history as the first sitting president in the Supreme Court’s 235 years to be present for oral arguments, according to . The case, which has prompted more than 40 amicus briefs from a wide range of groups, has the potential to alter the distribution of authority between Congress and the president and to significantly impact U.S. trade policy for years to come, according to .

The central question is whether Trump exceeded his legal powers by invoking IEEPA to levy tariffs—ranging from 10% to 50%—on imports from nearly every trading partner,

. Lower courts have already ruled against these tariffs, with the Federal Circuit’s 7-4 decision stating that IEEPA does not authorize the president to impose such sweeping import duties, as detailed in . The appellate court relied on the "major questions doctrine," which requires Congress to clearly approve policies with major economic impact, a point discussed in . The Trump administration maintains that the phrase "regulate importation" in IEEPA includes the authority to impose tariffs, and argues that courts should defer to the executive branch on national security matters, according to .

The implications are enormous. By September 2025, tariffs enacted under IEEPA are projected to have brought in $89 billion, helping to reduce the federal deficit and fund programs such as port fees for ships linked to China, according to

. If the Supreme Court overturns the tariffs, the government could face the daunting task of returning more than $100 billion in duties, a process that experts say could take years and place a heavy financial strain on both importers and taxpayers, the report notes. For Trump, a defeat would threaten his hallmark trade policies, which he has promoted as vital for safeguarding American employment and national security, according to analysts at Invezz.

Constitutional experts and advocacy organizations have voiced concerns, pointing out that Article I of the Constitution gives Congress the authority to "lay and collect duties," a responsibility it has traditionally delegated to the executive only under certain circumstances, as reported by ABC News. The Brennan Center for Justice contends that permitting IEEPA to justify tariffs would amount to an "unconstitutional delegation" of legislative power, undermining checks on presidential authority. In contrast, the Trump administration argues that striking down the tariffs would weaken America’s leverage in international trade talks and embolden foreign rivals.

The possibility of Trump attending the hearing lends additional significance to the case. While previous presidents have participated in Supreme Court ceremonies or appeared as attorneys, none have sat in on oral arguments, the Japan Times notes. His attendance would highlight the personal importance of the case and could signal either the administration’s confidence or its sense of urgency as the justices deliberate. The Supreme Court’s ruling, anticipated by the end of the year, will ultimately decide whether the president’s tariff approach will be upheld or struck down amid legal and constitutional scrutiny.