The Overton Window is "the range of policies politically acceptable to the mainstream population at a given time". Thanks, Wikipedia.
We might guess that, say, policies emphasising human rights fall within today's Overton Window, while policies designed to exclude on grounds of discrimination, race, gender, et cetera, fall outside it.
The Overton Window shifts over time. It expands, contracts, moves left, moves right, across a spectrum ranging towards more freedom at one extreme and less freedom at the other. More relaxed at one extreme and more uptight at the other. More intolerant, tolerant. Nice, nasty.
You get the idea.
Why has the UK government just introduced a three-tier restriction system? Because the idea of a national lock-down has moved outside today's Overton Window for anti-Covid policies.
And actually, because none of our political leaders seem able to think of anything else. While the government's pushing a three-tier restriction system, the opposition is calling for a circuit-breaker.
By now, I'd guess, the mainstream population has worked out that lock-downs are just a way of kicking the proverbial can down the road.
So our politicians are arguing about different ways of using foot-power to convey the cylindrical metal container further along the street.
This isn't leadership. Seems to me that leadership would be acknowledging what the mainstream population is beginning to understand - that we're stuck with this virus for the foreseeable future.
Which would mean finding ways to survive, prosper, socialise, support each other, et cetera, with the virus ever-present in the background. Not just finding euphemisms for: "Stay indoors until the clock turns back to 2019."
I suspect that even the government's assertion of control over the situation is moving outside the Overton Window. Nobody wants to hear that we're going to "beat" the virus, or indeed that we're going to fight it on the beaches, et cetera.
Because we're not.
There may be a vaccine, and it may eradicate the virus as effectively as we've eradicated flu or, say, the common cold. There may be enough doses for everybody to get one without argument.
Seems to me we've got to the point where we're crazy to argue about lockdowns being harsh or not-so-harsh. Long-term or just a couple of weeks.
What's killing us is that we live in a world where low-paid workers can't afford time off just because they're infected with a life-threatening virus.
"I know I'm contagious, but I can't afford to self-isolate."
One of the flaws in test'n'trace is that the vulnerable-to-infection, soon-to-be-contagious people can't afford to be found by the test.
They walk among us, selling us things.
Maybe we should care for them?
Would that be a more effective strategy than depriving them of their livelihoods?
Irrelevant footnote. The film Deep Impact (1998) surfaced on Freeview the other night. I know this because I switched on just in time to catch [spoiler] the briefing scene, in which US President Tom Beck (Morgan Freeman) announces, first, that the world is facing an "extinction-level event", an ELE, and secondly, that the world's governments, together, have worked out a way to deal with it.