The decision that will define the PM’s fate as well as the country’s

Boris Johnson is back at work, at least in part, after several weeks of what are almost certainly the best headlines he’ll ever get.

The problem for him is they were the result of his being seriously ill, and now for the birth of his son, with partner Carrie Symonds.

At such a time, most people have the decency to see a human being facing critical illness and fatherhood (again), and leave politics by the wayside.

At a time of national crisis, when the media is desperate for good news stories too, that sense is heightened. Johnson provided good news first in recovery and then in new parenthood. But he may enjoy what comes next far less – he is about to face perhaps the hardest few months of any prime minister since his beloved Churchill, and will do so after several weeks away from the centre of power.

Never a man praised for his commanding grip of detail, Johnson will be able to fairly complain to colleagues he has missed weeks of decisions, of details, of evidence and of nuance – only to find himself having to catch up from a standing start.

He can expect little sympathy: this is the job he asked for, and fought tooth and nail for throughout his entire adult life.

Johnson is a man acutely aware of history – at least in the sense that he would like to be remembered by it, and keeps one eye firmly on his legacy.

For a man who has so obviously wanted to be a leader in a time of national crisis, it is as if he is the apocryphal bearer of the cursed monkey claw, granted his wish but in a way that gives him nothing he actually wanted.

The PM must be aware by now that no-one gets a political win from a pandemic. The true death toll in the UK is already likely well above 40,000, and there is a litany of missed opportunities, mistakes and U-turns at which future inquiries may lay blame.

His role thus far, and the decisions he took before his illness, will be central to those inquiries. In the short term, rows over why the UK didn’t include itself in an EU scheme on ventilators may be what bites – but in the long run it is questions over whether Johnson acted too late, or took risks that other leaders didn’t, that – along with PPE shortages– could become his legacy.

He may have public support for now, but that can easily evaporate once a crisis passes.

Taking the fall for errors already exposed are what other ministers are for – Johnson has not been above letting deputy heads roll on his behalf before – and some speculate Matt Hancock is being framed up for that role.

But the real trick for Johnson to insulate himself from accountability for early errors and inattention – to get out of political jail – is to try to make them irrelevant. If he can get out of lockdown okay, his reputation will stay intact. After all, he might reason, who really holds the debacle at Gallipoli against Churchill?

In the great scheme of things, if Johnson can guide the UK out of lockdown in a way that avoids a second – potentially more severe – peak of infections, and leaves the UK less economically damaged than other

countries, his overall response will be hailed as savvy.

It is in Johnson’s political interest – indeed it is in all of our interests – to get the outcome right. So far so good. The problem is that working out how to do that is virtually impossible, and comes with a huge flurry of almost irreconcilable pressures and the need for almost superhuman assiduity and scrutiny… not characteristics with which the PM is associated.

Generally speaking, over-reacting to a crisis comes at a political price, but not a particularly high one – especially as it is virtually impossible, even with hindsight, to determine whether a response is an over-reaction or whether the response was essential to avert the crisis.

Some say the millions spent tackling the Millennium Bug were evidence of wasteful official panicking, as the year 2000 came and everything was fine.

The experts involved insist that this was only because of the spending.

When it looks like we face a major emergency, the rules on wastefulness are largely thrown out. When the government stockpiled millions of doses of Tamiflu during the swine flu epidemic – ultimately not needed – it later faced backlash for ‘wasting’ money on the unused doses.

The row, though, became something of a storm in a teacup: the public are sophisticated enough to understand it is better to have drugs and not need them than to face the opposite scenario.

The response to coronavirus is following some of the same principles: the UK government ordered $20 million of tests for the virus, without being sure they worked, in the hope that they would – as others would have snapped up first refusal otherwise. In the circumstances, the calculus might be worthwhile.

Similarly, the Bill and Melinda Gates Foundation is funding operations to scale up production of at least seven different possible vaccines, most if not all of which will not work.

It is worth wasting the money to save the time.

Johnson’s early response to coronavirus was characterised by the opposite: austerity had left the UK under-prepared, with its stockpiles neglected.

The politics of the next phase of the crisis would seem to point one way: there’s no such thing as overreaction. For a pandemic of this scale, though, the calculus is different: the costs of lockdown are absolutely huge, and increase dramatically as the duration of lockdown extends.

Businesses can survive a few weeks – maybe a month or two – of severe disruption, with government support.

But as we roll into month three, four, or even beyond, that gets far harder – and once some businesses fail, it can cause a cascade.

Suppliers lose customers and fold themselves. Their workers can no longer afford to pay their bills or buy anything else. Once dominoes start to fall, they just keep dropping.

That requires the government to do everything in its power to pause the economy while it’s in lockdown.

But that runs against the politics and economics of almost everyone in Johnson’s cabinet.

Rishi Sunak is not a man who wants to be remembered for blowing up the UK’s national debt, hugely expanding its welfare state, and effectively nationalising multiple industries.

Beyond that, Johnson’s political base among Brexiteers – especially in the commentariat – are those most likely to chafe against continued coronavirus restrictions, and want the world to get back to ‘normal’.

Johnson has to balance very real costs and risks alongside balancing often contradictory political risks.

The cost of getting it wrong could be horrendous.

The Spanish Flu of 1918 killed dramatically more people in its second peak than its first. If we relaxed restrictions too far and too fast, by the time we spotted it, the damage would

continue to kill thousands for weeks into months – assuming a second lockdown could be agreed and enforced.

The practical way to ease lockdown is to wait until we are entirely ready to begin – having as low a base rate of coronavirus in the cases as possible, probably in the tens of thousands, not hundreds as estimated now.

It means having a very thoroughly tested track-and-trace infrastructure of a sort we have never had in the UK before (and for which the app won’t even be ‘technically’ ready for two to three weeks).

It means being the bearer of bad news for those wanting to get back to the pub. Getting coronavirus ‘right’ from here on out – securing the decent legacy Johnson wants and escaping the blame for earlier mistakes – means acting against almost all of his political instincts, resisting the easy headline, the short-termism, and the optimism.

Throwing out the bluster. Paying attention to the details. Johnson needs to emerge from his near-death experience as a changed politician, for an extreme era.

Believing that the supremely-confident, aristocratic old Etonian could really alter his approach to the world in his mid-fifties is quite the leap. If he cannot change, he may find that he has recovered from his illness only to engineer the demise of the political career he worked his whole life to secure.

At least he would know which Greek hero that course most closely resembled.