The United States has reaffirmed that it will not abandon tariff deals already concluded with a range of trading partners, including the United Kingdom, the European Union, Japan and Switzerland, even as the administration navigates legal and political challenges to its broader tariff policy.

The assurance came from United States Trade Representative Jamieson Greer in a recent interview, in which he insisted that existing agreements remain valid and will be honoured by Washington.

Greer’s comments follow a ruling by the US Supreme Court that found key elements of President Donald Trump’s expansive tariff programme illegal under the emergency powers statute initially used to impose them.

In response, the Trump administration enacted a new global 15 per cent tariff under the Trade Act of 1974, which is legally durable for up to 150 days without explicit congressional approval, as it seeks to maintain leverage in trade negotiations and provide continuity for business planning.

The trade representative stressed that the new baseline tariffs are distinct from the bespoke arrangements struck over the past nine months with around twenty countries, which he described as “good deals” that the United States intends to honour and expects its partners to respect as well.

Among these arrangements is the Economic Prosperity Deal with the United Kingdom, agreed in mid-2025, which set preferential tariff terms on a range of British exports and has been welcomed by business leaders in both countries as a framework for deepening economic cooperation and market access.

Officials in London and Brussels have sought clarification amid concerns that the legal uncertainty surrounding the broader tariff regime could inadvertently undermine those agreements.

British government representatives have publicly expressed confidence that the preferential terms negotiated with Washington will continue, while European Union officials have underscored the importance of commitment to their own joint trade statements agreed last year.

Trade experts note that maintaining stability in existing agreements is critical for global markets and investor confidence, particularly as the United States pursues an assertive trade policy that has seen negotiations with partners including Japan, Canada and others over tariff reductions and market access.

The reaffirmation of commitment is also seen as a pragmatic response to criticism from allies that abrupt reversal or abandonment of negotiated terms would erode trust and complicate broader diplomatic and economic ties.

With the legal and political landscape around tariffs still evolving, Greer’s remarks aim to reassure partners that the United States will continue to uphold its negotiated commitments while adapting its legal authorities to sustain its trade agenda.