IN 1546 Girolamo Fracastoro, a doctor and poet, published an elegant theory of contagion. Infections spread in three ways, he argued: by direct contact, via an intermediary, or at a distance, through the air. In medicine, his theory is now considered quaint. In economics, however, it still works pretty well.
On August 10th President Donald Trump sent a pathogenic tweet, announcing a doubling of tariffs on Turkish steel and aluminium. It followed earlier sanctions on two Turkish ministers involved in detaining Andrew Brunson, an American pastor, on dubious charges. The lira, which had already lost 38% of its value since the start of the year, shed another eight percentage points in the tweet’s aftermath.
Early medical scholars believed gluttons were more susceptible to disease than cleaner-living folk. Similarly, Turkey has become vulnerable to financial disorder through macroeconomic intemperance. Businesses have borrowed heavily in foreign currencies. The government, which has…
