Why UK-US divide on Iranian nuclear deal matters

European powers, most notably Britain, have rebuffed US President Donald Trump’s Oct. 13 refusal to certify that the landmark nuclear agreement with Iran meets congressional requirements. Issuing a joint statement almost immediately afterward, UK Prime Minister Theresa May and her French and German counterparts reasserted their commitment to the nuclear deal, expressing concern over Trump’s new Iran strategy.

Since then, the British government has continued its staunch defense of the 2015 Joint Comprehensive Plan of Action (JCPOA). Speaking at the Chatham House London Conference on Oct. 23, Foreign Secretary Boris Johnson praised the JCPOA’s achievements in curbing Tehran’s path to a nuclear weapon. While expressing apprehension over Iran’s regional behavior, Johnson prescribed further engagement with Tehran and warned against disrespecting the Iranian population — a subtle reference to Trump’s inflammatory rhetoric. Given May’s emphasis on maintaining good relations with Trump, not least to secure a trade deal with the United States following Britain’s departure from the European Union, the UK’s vocal support for the JCPOA is particularly significant, marking a shift from the prime minister’s previous Trump strategy and the making of an independent British foreign policy toward Iran.