The Governor of California has now taken the drastic step of ordering all 40 million residents to stay at home. The measure applies across the entire state and it is mandatory, though people are permitted to go outside to buy food, medicine and petrol.
This is an extraordinary decision. The most successful economy in America, and the most dynamic in the world, is shutting down. The largest state in the union is closed for business - in fact closed for anything. We are in truly unprecedented territory.
This dramatic move by Gavin Newsom follows his estimate that over half of California’s population - 56% - is likely to be infected by Covid-19.
That’s a number that will certainly overwhelm the state’s heath care system.
Tens of thousands of Californians will need treatment and there are nowhere near enough hospital beds or ventilators.
Justifying such draconian steps, Newsom said: “This is not a permanent state, this is a moment in time. We will look back at these decisions as pivotal.”
New York may soon decide to go the same route. The NYC mayor, Bill de Blasio, has already suggested it may be the best strategy.
It is certainly striking that while California presses the emergency button and Britain is choosing a different route. Schools are only closing today, pubs remain open, and talk of a London lockdown were yesterday dismissed by Downing Street as premature.
Seen from this side of the Atlantic, the different decisions in London and Sacramento underline the very real risk that Boris Johnson is running, both politically and (much more significantly) in terms of people’s lives.
The Prime Minister may be correct. Perhaps his nuanced strategy - trying to shape behaviour but not enforcing any measures - is a perfectly valid middle course, and right for Britain.
But if California turns the corner, and the UK faces the nightmare of an entrenched pandemic that it can’t contain, then people may wonder why he didn’t take the same drastic action enforced in California, Italy or France.
What is also clear this morning is that state governors have stepped into the vacuum of leadership left by President Trump.
Donald Trump’s rambling and boastful White House briefings, often at odds with the medical and scientific consensus, and with bizarre asides about the media and other favourite targets, have become a national embarrassment.
So Governors, mayors, and hospital executives are being forced to improvise. It means a patchwork of steps. But with the Covid-19 hurricane on the horizon there is no more time to waste.
Coronavirus: Everything you need to know