For a brief moment this winter, it looked as though one of the biggest questions hanging over the Trump administration’s trade agenda had finally been answered. In February, the Supreme Court ruled that the President could not use the International Emergency Economic Powers Act (IEEPA), a law designed to address foreign threats and national emergencies, to impose sweeping tariffs on imports. After months of litigation, billions of dollars in collections, and no shortage of constitutional debate, the Court had closed the door.

Or so it seemed. The administration’s response was immediate. After the Court closed off IEEPA, the White House turned to Section 122 of the Trade Act of 1974, imposing a temporary 10 percent import surcharge. In the months that followed, USTR opened new Section 301 investigations, including forced labor inquiries covering 60 economies, and last week proposed tariffs based on those findings. The White House also continued expanding its Section 232 tariff regime, including new and revised tariffs on steel, aluminum, copper, and other national security-related imports.

The lesson appears to be that modern tariff policy resembles less a carefully constructed legislative framework than a sprawling collection of executive authorities accumulated over decades, waiting to be rediscovered whenever circumstances require.

The Supreme Court’s ruling was unquestionably significant. The Court held that IEEPA does not authorize tariffs and emphasized that when Congress delegates tariff authority, it generally does so explicitly. The decision invalidated a centerpiece of the administration’s trade strategy and reaffirmed that the Constitution assigns tariff powers to Congress, not the President.

Yet even as lawyers were parsing the implications of the ruling, the administration was already shifting gears. Section 301, the authority behind the latest proposal, has existed for decades as a mechanism for responding to unfair foreign trade practices. Section 232 authorizes tariffs in response to national security concerns. Neither was touched by the Court’s ruling.

Before the Supreme Court struck down the IEEPA‑based tariffs, importers had paid as much as $166 billion in duties under the program, and more than 50 million entries were affected. Many of those entries remain unresolved. Some importers may receive refunds through routine administrative procedures. Others may need to pursue litigation. The final price tag remains uncertain.

Uncertainty, you may notice, is the theme here.

Tariffs are being treated as though they are a straightforward source of revenue, a simple tool capable of financing government programs while simultaneously reshaping global trade. In practice, they are taxes layered onto a complex and constantly evolving economic system. They generate revenue, certainly. They also generate lawsuits, retaliation, exemptions, appeals, and, occasionally, refund obligations measured in the tens of billions of dollars. What they rarely generate is simplicity.

Nor is there any reason to assume the latest tariffs will prove more durable than the ones they replaced. Section 122 has rarely been used and was designed as a temporary response to balance of payments problems, not a long-term trade strategy. The new Section 301 proposal will almost certainly face scrutiny over both its legal rationale and scope. Even Section 232, long considered the administration’s strongest tariff authority, remains the subject of recurring legal and political challenges.

That does not mean these tariffs will ultimately be struck down. It means the same uncertainty that surrounded the IEEPA tariffs now hangs over many of their successors. Businesses, consumers, and taxpayers are once again being asked to make long-term decisions around policies whose longevity remains very much an open question.

Speaking of open questions, here’s another one: Why is so much of American tariff policy being made this way?

The Constitution gives Congress authority over tariffs. Yet, like in many areas, lawmakers have gradually delegated portions of that authority to the executive branch. The story of the administration’s tariff policy is often about its battles with the courts, but the more enduring story may be about Congress and the powers it has chosen to give away.

The Supreme Court’s decision may have narrowed one avenue, but it did not change the underlying architecture. That is why the administration’s response was so swift. There was no need to rethink the broader strategy. Another authority was already available. And another may be waiting after those fall.

This is not really a story about one administration or one court decision. It is the inevitable product of Congress stepping away from its constitutional role and leaving tariff policy to be improvised. That is the real legacy of our modern tariff regime, if we can call it that. Not protectionism. Not industrial policy. Not even revenue. But uncertainty.