Korean nuclear talks

President Trump and the governments of North Korea and South Korea are combining to create sky-high expectations for a diplomatic breakthrough on the North’s nuclear programme. In the case of the Koreans, that’s evidently the result of careful and clever tactics. In Mr Trump’s case, it looks more like empty and self-aggrandising bluster. The result is that his bet on an unprecedented summit with the North Korean leader is looking riskier than ever.

Mr Kim just promised his people he would propel the country’s decrepit economy into an “upward spiral”, something that would require the lifting of UN economic sanctions ... Mr Trump seems all too happy to play along. But is he prepared for a negotiation on something less than the full and quick elimination of North Korea’s arsenal? Would he accept the multistage deal Mr Moon is promoting? What interim concessions would he be willing to make to preserve Mr Kim’s easily reversed testing freeze?

If he has carefully thought through these questions, there is little sign of it. Instead, he promotes the prospect of a breakthrough, while promising to walk out if he doesn’t get it. That could be a recipe for failure. Mr Trump and his aides should work out what sort of outcome from the summit is both realistic and in the American interest, and then design a careful strategy to obtain it. That, after all, is what the Koreans are doing.