What does it mean to be Keynesian? It was the British economist John Maynard Keynes who declared that when, like today, economic growth grinds to a standstill and businesses fail to provide enough jobs, governments have the ability, and the duty, to fill the gap.

Keynes developed his theories in the wake of the 1929 stock market crash and the Great Depression.

He urged raising "aggregate demand" by loosening credit, spending on public works and cutting taxes. The government should run deficits, Keynes argued, but should be careful to pay them down when people were working again and wealthy enough to pay taxes.