Today, Donald Trump’s legal team is appearing before the United States (US) Supreme Court to defend his use of emergency powers to impose tariffs on America’s main trading partners.

The decision could reshape the balance of authority between Congress and the presidency, and it will determine how far Washington can go in weaponising tariffs as a tool of foreign policy.

The case began in April 2025 at the US Court of International Trade, which ruled a month later that many of the tariffs were illegal. Trump appealed, but the US Court of Appeals largely upheld the lower court’s decision. The Supreme Court hearing will likely mark the final step in determining whether Trump’s use of emergency tariff powers was lawful.

For South Africa, the ruling matters deeply. Despite several meetings between its trade negotiators and White House officials this year, Pretoria still has no deal, while the great majority of other countries have secured lower tariff rates. India, a fellow BRICS member, has gone beyond trade, and finalised a ten-year defence pact and is close to having tariffs on Indian imports to the US cut from 50% to 15%. China, despite its fierce rivalry with Washington, has moved toward détente after a meeting between Xi Jinping and Trump last week.

South Africa was classified by the Trump administration as a: “worst offender” on trade and hit with a 30% tariff, one of the highest rates imposed on any country. That punishment reflected Washington’s frustration with Pretoria’s foreign policy, particularly its ties to Iran, its case against Israel at the International Court of Justice, its threat to the property rights of American investors in South Africa, its taxation of capital invested by American firms, and its alignment with Russia and China.

Despite South Africa’s misaligned foreign policy, sources in Washington say the White House wants Pretoria to succeed as a prosperous and democratic emerging market. The administration, however, is seeking a broader trade arrangement, more aligned with Trump’s transactional: “America-first” approach. An independent Afrikaner delegation proposed just such a framework, centred on processing critical minerals in a special economic zone in Saldanha for export to the US. The plan included relaxed Black Economic Empowerment rules to attract capital and counter China’s mining influence in Africa.

A special dinner hosted in Washington in honour of South African golfer Gary Player in September, offered a pivotal opportunity to strike a trade deal. The White House invited South Africa’s chief trade negotiator, Alistair Ruiters, to present a joint, broader trade proposal alongside the Afrikaner delegation. Ruiters declined.

That decision, along with a series of other actions, confirms that South Africa is not prioritising closer ties with the US. The country has been without a permanent ambassador in Washington for nearly two years, and several candidates proposed by President Cyril Ramaphosa were rejected by the US State Department over their ties to Iran and public criticism of America.

Most recently, South African intelligence services were revealed to have orchestrated a letter critical of Trump under the guise of an independent civic initiative that was leaked to journalists. There is a growing suspicion that corrupt government leaders in Pretoria may even be acting under external Iranian, Russian, and Chinese influence to deny America access to South Africa’s economy.

Now, as the US Supreme Court prepares to decide whether President Donald Trump had legal authority to impose the sweeping tariffs, South Africa risks further isolation. If the Court upholds the tariffs, countries that negotiated early will retain favourable access. If the court strikes them down South Africa's hostile stance against the US will leave its negotiators on the back foot as the Trump administration looks to alternative mechanisms with which to maintain tariffs

It is important to note that the cases challenging the tariffs in lower courts were decided by panels with majorities appointed by Democratic‑leaning presidents. By contrast, the Supreme Court now has a conservative (Republican‑appointed) majority, which may favour a broader view of executive power.

But even if the Court rules against President Trump, experts say he has other legal tools at his disposal.

South Africa, having rejected repeated opportunities for collaboration, risks gaining nothing from either outcome.