When the Democrats won Georgia’s two Senate seats last week, US president-elect Joe Biden greeted the victory — which brings his party control of Congress — with a statement that voters “want action on the crises we face and they want it right now”. It was undoubtedly a conscious echo of Franklin D Roosevelt’s 1933 inauguration speech, when the New Deal president vowed “action — and action now”.

Roosevelt, as Mr Biden will, took office amid a deep economic crisis. So did Barack Obama, whom Mr Biden served as vice-president. Both predecessors acted to end the economic downturn. But only one fundamentally reshaped the way the US economy worked.

Beyond recovery policies, FDR used his crisis to roll out big structural changes in very little time. These reordered economic relations, were politically sticky and were hard to reverse once in place: deposit insurance, mortgage reinsurance and social security. The federal minimum wage followed in his second term. The programmes imparted long-term economic security to those they covered, even though several were unconscionably designed to exclude black Americans.