In 2001, George W Bush urged Americans to go shopping. That was after the September 11 attacks. Donald Trump wants Americans to buy stocks on the bet that something bad will not happen: the spread of the coronavirus infections at home. His gamble could pay off. 

But the US president is staking his credibility on something that is mostly beyond his control. Short of severing all links to the world, which would trigger a recession, the virus will almost certainly spread in the US, say the experts, including those who work for Mr Trump. At which point, who will he blame?

So far Mr Trump has avoided blaming anyone, including China. His priority is to keep the economy growing in the build-up to the November presidential election. Officials have been told to talk down the threat of the coronavirus.