There’s a long way to go before Trump can declare victory in his trade war

There is no shortage of quotes by Donald Trump that his opponents have tried to use against him — few of which have so far damaged him politically, still less embarrass the man himself. But there is one which really does have the potential to cause him harm in this year’s presidential election: his claim, in March 2018, that ‘trade wars are good, and easy to win’.

That isn’t looking quite so clever now, two years later when the trade war that Trump started with China is still far from won. The deal signed today by…