If the Supreme Court Sides with Trump, Congress Loses Its Oldest Power

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When the First Congress convened in 1789, it didn’t start with grand speeches about democracy or the rights of man. It passed a tariff bill. The Tariff Act of 1789 was one of the first substantial things the new government did, and for good reason: the federal government needed money, and tariffs—taxes on imported goods—were how it would get that money. For the next 150 years, these taxes generated more than 87 percent of federal revenue in some periods.

The Constitution is explicit about who gets to impose these taxes. The Constitution says Congress alone has this power to “lay and collect Taxes, Duties, Imposts and Excises.” Not the president. Not federal agencies. Congress.

Over the past century, lawmakers have gradually given presidents more power by passing laws that let them do it. Now the Supreme Court is deciding whether that transfer has become permanent.

If the Court sides with Trump, lawmakers lose functional control over their oldest constitutional power. They could still pass laws, but the barriers to take back tariff power would be so difficult that the president would keep this power permanently.

How Tariff Power Shifted to the President

Lawmakers didn’t surrender this authority in one dramatic moment. It happened gradually, through decisions that made sense individually but that collectively took power away from Congress.

The story starts with the Great Depression. By 1930, legislators had spent decades passing increasingly protectionist bills, leading to the Smoot-Hawley Tariff Act, which was a disaster—a legislative failure that raised rates on thousands of products, sparked global retaliation, and deepened the economic crisis. Lawmakers decided they needed a different approach.

In 1934, they passed the Reciprocal Trade Agreements Act. Congress set boundaries: they said what goal they wanted (more open trade), how much authority the president could exercise (up to 50 percent adjustments), and under what constraints (through negotiated agreements, not unilateral action).

Over subsequent decades, those limits eroded. The Trade Expansion Act of 1962 let presidents impose tariffs on goods that could harm America’s defense. The Trade Act of 1974 expanded that authority further. By 1977, when lawmakers passed the International Emergency Economic Powers Act, the framework had evolved substantially—but they believed they were maintaining control through the requirement that presidents declare national emergencies, which they could theoretically terminate.

Trump didn’t stay within the limits Congress had set. He claimed IEEPA gave him power to impose tariffs on almost anything, from any country, in any amount, for as long as he wanted—even though the law never mentions tariffs.

Why Congress Cannot Reclaim This Power

Here’s what Congress would need to do to take back this power. First, lawmakers would need to agree that the Court’s decision was wrong. Second, they’d need to write a law detailed enough to hold up in court. Third, both the House and Senate would need to pass it with enough votes to override a veto. A two-thirds vote has become almost impossible to achieve.

Even with public support and bipartisan sponsorship, a bill lacks the votes to overcome a presidential veto. Once power shifts, it doesn’t shift back.

Congress’s Lost Expertise in Tariff-Setting

If the Supreme Court approves presidential power over tariffs, the effects go beyond losing this power. Congress gradually loses the ability to make these decisions at all.

Congress once had real expertise in setting tariff rates. In the nineteenth and early twentieth centuries, major bills required months or years of legislative development. Lawmakers kept detailed information about industries, costs, competition, and trade. Committees developed deep expertise.

Congress has lost much of that expertise. As the president and executive agencies took over, Congress stopped hiring experts on tariffs. Committee staff shrank. Experienced people left. Knowledge about how to do this work disappeared. Congressional Research Service budgets have faced constraints that limit deep expertise in specialized areas like trade.

The longer Congress doesn’t use a power, the more it loses the ability to use it. A future Congress trying to take back this power would face three problems: political opposition, Supreme Court precedent against it, and the fact that Congress would have lost the expertise to make these decisions. Experts would have moved to executive agencies or law firms. Committee structures might no longer exist. Knowledge about how to make these decisions would be gone.

A Supreme Court decision approving presidential power over tariffs would make this problem worse, because such a decision would give Congress no reason to keep experts or the systems needed to make these decisions.

The Broader Pattern: Power Shifts Across Policy Areas

Congress has gradually given up power over foreign policy, war, emergency spending, and regulations. War powers offer a useful comparison. The Constitution says Congress has the power to declare war, using language as clear as its power over tariffs. But through military authorizations and by not objecting when presidents use force, Congress has lost real control over when America goes to war.

War powers have eroded because Congress didn’t stop presidents from taking power, not because courts approved it. Congress still has the legal right to cancel the AUMF and cut off funding. This tariff case is different because a Supreme Court decision would officially transfer the legal power from Congress to the president. If the Court says IEEPA lets the president impose tariffs, then Congress can’t claim it’s allowing it to happen or that it lacks the ability. Any future effort by Congress to take back this power would face political opposition plus a court ruling saying the president legally owns it.

How the Court’s Ruling Will Shape Presidential Power

If the Court says IEEPA lets the president impose tariffs and that this is constitutional, then Congress would have to pass a new law to limit it—but the Court would have already approved the president’s interpretation. Congress could technically pass a law saying IEEPA doesn’t give the president this power, but the president would veto it.

If the Court uses broad language about presidential power over trade or national security, it could make it harder for future courts to limit presidential power in other areas. Justice Kagan warned that allowing unlimited presidential power over tariffs would mean Congress had given up its power to the executive branch.

Conversely, if the Court rules against Trump, the law would remain unclear. Congress could later pass a law saying IEEPA does give the president this power.

The Difference Between Legal Power and Real Control

Congress would lose real control over tariff policy if the Supreme Court says the president can impose them. The loss wouldn’t be in the legal right to pass laws, but in the real ability to control tariff policy. Once the president has the power to impose tariffs without Congress, once the Court approves it, once the executive branch builds the systems to do it, and once everyone expects the president to decide—Congress would find it nearly impossible to take the power back.

Congress still has the legal power over war, spending, and regulations, but the president has taken real control of all three. Congress still has the legal right; it’s lost the real ability to use it. Tariff power is Congress’s oldest power. The Framers gave it to Congress, and Congress used it directly for more than 150 years. If the Supreme Court approves moving this ancient congressional power to the president, it would be a major shift in how government power is divided.

When the Decision Comes and What It Means

The Supreme Court usually issues major decisions in June, though this case’s economic impact might change that timing. Whenever it comes, the ruling will decide whether the power shift becomes permanent or whether Congress can still take the power back.

If it does, taking back the power would become so difficult that the shift would probably be permanent. Future Congresses could still pass laws, but they’d lack the expertise, political support, and legal basis to actually take the power back.

The case is about whether Congress can ever take back power once it gives it up, or whether that surrender becomes permanent once courts approve it. For an institution losing power in many areas, this decision matters far beyond tariffs. The Constitution gave Congress the power to tax imports. The question is whether Congress can ever take back power once it gives it away and courts approve it.

How Temporary Powers Become Permanent

When Congress gives power to the executive branch, lawmakers usually think they can still watch over it. They point to rules requiring reports, laws that expire, or Congress’s ability to review decisions as safeguards. But these safeguards usually don’t work. Reporting requirements become routine paperwork. Laws that were supposed to expire get extended automatically. Congress’s ability to review decisions requires huge majorities that are almost impossible to get in today’s divided politics.

Power given temporarily becomes permanent. What starts as limited power to solve one problem becomes broad power the president uses all the time. The expertise and political desire to take back the power gradually disappear. This pattern has happened across many areas of policy over the past century. Emergency economic powers from the Great Depression became permanent presidential powers. War powers given for specific conflicts became blanket approval for military action anywhere. Regulatory powers given to solve specific problems became broad power for agencies to make policy without Congress having a real say.

In each case, the law suggested Congress still had final control. They could pass new laws. They could cut off funding. They could hold hearings. But the practical barriers to using these powers grew so high that the power shift became impossible to undo.

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