The Economist does not know Mr Warsh’s views on meteors or volcanoes. Even Mr Warsh grants that, in a crisis, clear communication is “prudent”. Worse, Mr Trump seems determined to make Mr Warsh’s life difficult. It is possible that, in an attempt to avoid this, Mr Warsh is already trying to get the market to do his tightening work for him. The danger is that higher yields might instead reflect the risk of Mr Warsh’s experiment going wrong.