When a snail is threatened, it has one response, and one response only. It cannot run, because it is a snail. It has no weapons, because it is a snail. Unlike some tropical animals that can change colour, or confuse or dazzle a predator, a snail has no ability to use subtlety or disguise or strategy to evade a threat. The only thing a snail has, of course, is its shell. And so, it does not matter whether the threat is a bird, or a human, or a fox: If threatened, the snail will retreat into its shell, and hope for the best.

Sometimes it works. Sometimes it does not work.

In Ireland, today, faced with a threat, there are a growing number of voices advocating for the snail strategy.

“Shut the borders”, they say. “Seal the ports”. “Lockdown until the virus is gone, and until it’s safe to come back out”.

The only way that zero covid, as it’s known, can work, is if the country adopts the pose of a snail. Or that of North Sentinel Island.

North Sentinel Island, for those of you who don’t know, is a little island in the Indian Ocean, inhabited by a race of people known as the North Sentinelese. The North Sentinelese have no contact with the outside world. They are a primitive tribe, whose contact with the rest of the world is non-existent. They have killed, so far as we know, everyone who has ever set foot on their island. The most recent victim, an American Christian Missionary called John Allen Chau, who believe himself obligated to bring the word of god to North Sentinel Island back in 2018, was swiftly killed.

Zero Covid sounds reasonable enough, in the abstract, which is presumably why it has gained so much popularity recently. It’s exactly what it sounds like: Instead of trying to manage Coronavirus, we seek to eradicate it altogether in the Irish population, and prevent outsiders travelling into Ireland, based on the risk that they might bring more Covid with them. For it to work, you lock the country down, seal the borders, and, once cases have gone down to almost zero, you open the country back up again – but keep the borders closed.

The problem, of course, is that unless every country in the world does the exact same thing, at the exact same time, you’re never really going to be able to open the borders back up again. Even with the advance of the vaccine, it could take years for the whole world to be covid-free. Ireland’s vaccination programme is slow, but it’s light years ahead, for example, of many second and third world countries. Ask a Covid Zero advocate how long, exactly, the borders must remain closed for, and they cannot tell you. Here’s Leo Varadkar yesterday though, with a relatively conservative guess:

That means that your son or daughter in London won’t be home next Christmas. Tens of thousands of Irish emigrants, in other words, will be stranded abroad indefinitely. It means all business travel into and out of the country is done, for at least the next year. It means, in all likelihood, the collapse of the national airline, since Aer Lingus’s entire business is predicated on flights in, and out, of Ireland.

But it’s not just the travel: Zero Covid also means a much stricter, and possibly longer, lockdown than the one we already have. In order to open back up the domestic economy, we’d need to eradicate covid on the island altogether. That probably means, for example, no return to school until September, at the earliest.

And note the phrase on the island.

Because of course, there are two jurisdictions on the Island. Either Zero Covid is introduced North and South, or the border with Northern Ireland would have to be closed, too. Just a year ago, remember, the prospect of even mild trade barriers on the Irish border was regarded as such an unthinkable calamity that the Irish Government did everything short of declare a holy war on Brexit. If those mild restrictions were, as we were told, an unthinkable measure that would cause economic devastation, what would Zero Covid do?

And what of those who are saying today that Ireland would be in a much better position if we had just embraced Zero Covid a year ago, and shut the borders back then? Well, note that very few of them are observing that if Ireland had done that, our borders would have been closed to the outside world for almost a year now – with no end in sight. Because of the Covid spikes elsewhere in Europe, and the world, we’d have had to remain sealed. We’d be sealed today, in fact. With no end in sight.

For a small, open economy like ours, the costs are simply unsustainable. It’s a policy that would cut families off from loved ones almost indefinitely, frustrate business almost indefinitely, and still run the risk of it not working. It only takes a few people, remember, to sneak into the country to blow the whole thing up.

Shells are for Snails. They don’t always even work for Snails. The idea that a whole country can go into its shell, and hope that the big baddie goes away, might seem attractive in the moment. But when you think about it, it’s ludicrous.