The double dip is not a dance. It is the time-honoured tendency of the US economy to relapse into recession after a temporary recovery. Over the years, it has happened far more often than not. Notwithstanding frothy financial markets, which currently are discounting an uninterrupted V-shaped recovery, there is a compelling case for another double dip in the aftermath of America’s devastating Covid-19 shock.The daunting history of the US business cycle warns against complacency. Double dips –…