Even by recent standards of electoral pandering, the timing of Barack Obama’s WTO complaint against China was unsubtle. So too was his choice of venue for Monday’s announcement. Ohio may again turn out to be the decisive swing state in this election. Mr Obama’s complaint alleges that China is subsidising its auto-part exports – a sector on which most of Ohio’s remaining industrial base depends. His action was clearly tailored to Ohio concerns.

But the content – as opposed to the politics – of Mr Obama’s move falls short of egregious. Unlike section 421, which Mr Obama invoked in 2009 to impose anti-dumping duties on Chinese tyre imports, Monday’s action falls within the spirit as well as the letter of multilateral rules.

China may, or may not, have given more than $1bn in illegal subsidies to its auto-parts exporters, as the complaint alleges. But it is the WTO, and not the US administration, that will decide whether it is a case worth hearing.