It is natural that positions in trade negotiations will harden on the eve of a deal.
One of the darkest moments in the US talks with Canada to revise the Nafta accord in September last year came just four days before the two North American neighbours reached an agreement, as US president Donald Trump lashed out at Chrystia Freeland, Ottawa’s top negotiator.
We may well be at that stage in the US-China talks. In recent days, there have been multiple signs that officials in Washington and Beijing are having trouble closing the deal, and struggling to set a date for a “signing” summit between Mr Trump and Xi Jinping, the Chinese president.