Efforts to introduce US trade deals with Europe and Asia have been dealt a blow after a vote in the Senate.
Late on Tuesday, senators rejected a bill that would allow the president to speed trade deals through Congress.
This means that Barack Obama will not be able to fast-track trade pacts such as the Trans-Pacific Partnership (TPP) and Transatlantic Trade and Investment Partnership (TTIP).
The Senate voted 52 to 45, eight votes short of the 60 votes needed to pass.
The move sets back the adoption of the TTIP, a trade agreement between the US and European Union.
The aim of TTIP is to boost the economies of the EU and the US by removing or reducing barriers to trade and foreign investment. Some are concerned that TTIP could undermine governments’ right to regulate in the public interest.
TPP is a similar potential US trade pact with Asia and South America. It aims to boost growth in 12 countries in a trade zone covering 40% of the world economy through the slashing of tariffs.
The fast-track bill is vital for the creation of the TPP, according to a government spokesman in Japan.
The trade partnerships had been billed as a legacy-defining achievement for President Obama, but he has faced opposition from within his own party and labour unions.