1) It's too late (for this variant). So you can't act reactively.

2) When would you ever open then (since you need a proactive approach)?

3) How would trade look? I can't think of a single way of halting a contagious virus between countries that wouldn't completely shut us down as a race. The cost to humanity would be beyond imagination. Perhaps on the order of 100x-1000x that of corona.

Maybe you imagination is limited. China has done this precisely. They have kept the virus in check while limiting international travel and while being the world's factory. You open up when enough of your population is vaccinated.

I wonder why you feel that it is fine to say "too late" for this measure that obviously works. Do you also say too late to lockdowns, vaccine mandates, restaurant and schools closures, and mask requirements. If you don't, then maybe spend a moment thinking if your epidemic response is guided by your political allegiances

China is an authoritarian state that can almost anything it wants to do to limit the freedoms of its population. That same tactic won't work in (real) democratic countries, especially after 2 years of lockdowns.

New Zealand has a 14 day quarantine for international travelers: https://www.immigration.govt.nz/about-us/covid-19/border-clo...

Is New Zealand an authoritarian state?

A 14 day quarantine isn't a lockdown, even NZ is getting sloppy with virus measures. If the people there get tired of it there is nothing the government can do to stop them. In China you will get quarantined forcefully by the police state, and if you don't like it you can go to prison or get disappeared if you raise to big of a commotion.

New Zealand has cases, so what exactly is your point? The initial argument is that locking borders could prevent the spread of a highly contagious virus into a country. It cannot.

> China has done this precisely. They have kept the virus in check

According to their government...

> for this measure that obviously works

it obviously isn't since the various variations of the virus are spreading

Your last paragraph is begging the question: closing schools wasn’t required and was likely a major mistake. Closing borders just heaps more ineffective but costly action into the pile.

From the outside it looks like a lot of policies are reactive, they aim at where the target was days before, not where it is now or where we'll anticipate it might be by the time policies go into effect.

We already know we're acting on imcomplete, time-delayed information, i.e. we will only learn a few days later when the variant arrives in another country. So we have to compensate for that either by shutting everything down or by introducing artificial delays. And that's assuming all countries are testing and reporting the spread early. Some countries might lack coverage and thus act as dark hubs.

In America it would disproportionately affect working class immigrants who get a measly two weeks a year to see their families.

We do not have and shouldn't have a zero covid goal and negative tests + vaccine checks are a reasonable enough. AU/NZ are outliers, but there are countries with strict border policies like them but that failed to contain their spread, such as Australia's neighbor Indonesia. That suggests there's more to the story that requires further study. Australia + NZ are not good case studies for Europe + NA to follow because they are rich islands with limited ports of entry that get less international air traffic in a year than busy European or NA airports get in a month. Furthermore I don't see what the major quality of life improvements for Aussies/Kiwis has been as a result of their overly strict policies. They have a statistic they can be proud of but at what cost?

Schools were closed at the local and state levels. Closing the borders requires action at a federal level. That seems incredibly unlikely to happen.