The Trump administration has been coming to terms with an uncomfortable truth. Its flagship trade deal, the revision of Nafta into the United States-Mexico-Canada Agreement, signed by the three countries with much fanfare last November, is facing serious problems on the road to ratification by the US Congress.

This means it is unlikely to be approved by US lawmakers by the summer, the original timeframe pushed by Robert Lighthizer, the US trade representative. The bigger risk is that it stalls completely, and is never passed.

Both Mr Lighthizer and US president Donald Trump have stepped up their lobbying of members of Congress to try to speed things up, but it is far from clear that lawmakers are changing any minds. With Democrats in control of the House of Representatives, much depends on the approach taken by Nancy Pelosi, the Speaker, who has traditionally been sceptical of trade deals and is unlikely to want to give Mr Trump a legislative victory on trade heading into the 2020 presidential election race.