Early in 2018, Republicans in Washington ran an experiment: after passing a tax cut, they poured additional government spending into an economy that didn’t seem to need it. Democrats gave them the votes to do it. Most macroeconomists expected new jobs but also higher inflation.

The jobs came. The inflation did not. The experiment worked. In 2020, Republicans plan to repeat it, this time without the tax cut. They will shower money on to a hot economy. Democrats, again, have already helped them. US president Donald Trump will face many obstacles to his re-election next year. The economy will not be one of them.

The 2019 data has been hard to explain. Corporate investment collapsed. Confidence among chief executives dropped to a 10-year low. But unemployment has remained at or below 4 per cent for more than a year and a half. Working-age adults continue to rejoin the labour force. Hourly wage growth for workers not in management is at 3.7 per cent. Inflation remains stable and feeble.