S ince Donald Trump returned to the White House, American investors have received one shock after another—so it really takes something to get them to jump these days. Announcements that not long ago would have been bombshells, such as the president deciding to levy a tariff of 50% on copper or 30% on the European Union prompt a shrug. A rare exception came on July 16th, when Mr Trump seemed to contemplate sacking Jerome Powell, chair of the Federal Reserve, but even then the reaction was relatively muted: a pop in Treasury yields and slump in the dollar. Mr Trump reversed course; business got back to normal. The following day American stockmarkets hit all-time highs.