US President Donald Trump has announced plans to impose a 15% global tariff on imports after the Supreme Court struck down his previous trade measures, ruling that he had exceeded his authority under the 1977 International Emergency Economic Powers Act. Initially set at 10%, the tariffs will now be applied under Section 122 of the 1974 Trade Act, allowing them to remain for around five months before congressional approval is required.

The move impacts countries such as the UK and Australia, which had negotiated lower tariff agreements with the US, and exempts certain critical minerals, metals, and pharmaceuticals. While some US industries and officials see the tariffs as a way to boost domestic manufacturing and reduce the trade deficit, critics warn the policy could create a patchwork of trade barriers, hurt global economic growth, and complicate existing trade deals.

Trump’s tariffs, a key part of his economic agenda, have already generated at least $130bn in revenue, but the Supreme Court ruling marks a major check on his power and has sparked mixed reactions from US businesses and international trade partners.