Does the current pandemic seal the case against open borders?  Though I foresee many readers’ incredulity, the correct answer is: no way.  Why not?  Key point: Borders are already about 98% closed to immigration.  As I’ve explained before:

Let C=total number of immigrants – legal and illegal – who annually enter the U.S. under existing laws.

Let F=the total number of immigrants who would annually enter the U.S. under open borders.

Under perfectly open borders, C=F.  Under perfectly closed borders, C=0.  Where does the status quo fall on this continuum?  The obvious metric:

Open Borders Index=C/F

With closed borders, the Open Borders Index=0.  With open borders, the Open Borders Index=1.

Regardless of your views on immigration, it’s hard to see how your estimate of the actually existing Open Borders Index could exceed .05.  After all, there are hundreds of millions of people who would love to move to the U.S. just to shine our shoes…

Which brings us to the crucial question: How much protection have 98% closed borders given us against the pandemic?  The answer: Virtually none.

To successfully prevent the spread of infection, you would have to do vastly more than permanently stop immigration.  You would also have to permanently stop both trade and tourism.  As long as foreigners can fly over for a visit, or unload their goods on our docks, foreigners can and will infect us with their diseases.  Indeed, as long as natives can fly away for a visit, or unload our goods on other country’s docks, natives can and will infect us with their diseases.  The sad fact is that even very low absolute levels of international contact have been more than sufficient to spread infection almost everywhere on Earth.  The marginal cost of higher levels of contact is therefore minimal.  Do you really think any countries in Europe would be much safer for long if they had merely “stayed out of the EU”?

In fact, if you’re focused solely on preventing the spread of infectious disease, immigrants are plainly better than tourists and sailors.  Few would-be immigrants would be deterred by a mandatory health inspection prior to entry, because they expect large long-run gains.  For tourists and sailors, in contrast, a mandatory health inspection would often be a deal-breaker.  Remember: Even a simple visa requirement reduces tourism by an estimated 70%.  Just imagine the effects of a serious medical exam for every entering or returning international traveler.

Admittedly, you could bite the bullet of full isolation, but that’s crazy.  Hoxha’s Albania and Kim Il-Sung and Kim Jong-Il’s North Korea were awful for many reasons, but autarchy was plainly high up the list.  And to repeat, to make this work you can’t simply keep foreigners out.  You must also keep natives in – or at least tell them, “Once you leave, you can never come back.”

What about temporary travel restrictions to quarantine a severe international disease?  As I’ve explained many times, I am not an absolutist.  Given strong evidence that modest restrictions on mobility have dramatic benefits, such restrictions are justifiable – intranationally as well as internationally.  But that is – and should be – a high bar indeed.  The freedom of movement that we have lost is the freedom of movement that we have denied to non-citizens for a century.