I was looking forward to enjoying this book, but I left it disappointed. Maybe I'm not the right audience, because I'm already somewhat sympathetic to the idea of open borders, and Caplan approaches the issue as if he's arguing from outside the Overton Window. But in my point of view, the book's arguments are shallow and misguided.
The most amazing thing about this work is how much time it spends discussing the disparity in wealth and living conditions between the developed and developing world, without an inkling of insight on *why* this disparity exists. And yet, it presents open borders as a grand solution: a great generator of wealth and prosperity that can lift the living standards of the entire globe. How can you trust Caplan's solution to the problem when he gives absolutely no account of its cause?
Okay, to be fair, there is a section devoted to this issue. But the answer is offensively reductive: Culture. Caplan says (or rather, assumes) that the entire difference in prosperity between the first and third world is due to, essentially, "Western values," laissez-faire capitalism, and democracy. Never mind that one of the greatest examples of mass poverty reduction (which Caplan himself cites as an example of the benefits of free movement) was under the aegis of the authoritarian Chinese government. And never mind the long, bloody history of Western colonialism that ravaged much of the developing world leaving it at an enormous disadvantage. And never mind the current neo-colonial, capitalism-fueled world order which maintains a global pool of desperate, cheap labor to supply the consumerist and military demands of the developed world. I *would* say what "Western values" have done well for their societies is exporting the negative consequences of this order onto other countries... but in the case of my country (the USA), we have plenty of the suffering underclass right here at home.
So what does this mean for the arguments in the book? Again, you can only appreciate the impact of a change to a system if you understand the forces keeping it how it is. The world is not as simple as the economic model of independent actors making voluntary transactions. If the global underclass suddenly all had the ability to migrate into the developed world at will, the capitalist order that relies on their exploitation and desperation would be threatened, or at least reorganized. This could potentially put in jeopardy the global conditions that have facilitated the economic rise of the West whose culture Caplan lauds so much. And I'm not talking about conspiracies or anything — just forces of nature.
Consider the example of housing. In the USA, people are free by law to live and work anywhere. And yet many struggle to find jobs that can consistently put food on the table. Is it that there are no jobs? No: it's that people go where the jobs are. This increases demand for necessities (e.g. housing) and drives up their price. And since there is a large supply of desperate labor in certain sectors (particularly low-skilled work), the employers set the terms, and the result is a race to the bottom where wages are the minimum amount that can hardly support an individual. And the cost of housing doesn't go down because the housing supply is restricted: by the inherent scarcity of space, our system of property ownership, and especially local (democratic! Western!) laws and NIMBYism limiting what can be built and lived in, in order to protect existing interests and wealth. So the result is that you have many workers barely scraping by while commuting many hours to and from job centers like San Francisco or its South Bay every day.
So what would happen if the whole world's population could just up and move where the good jobs / living conditions are? Demand for housing in desirable areas would skyrocket and the issues plaguing San Francisco would be reenacted at huge scale. Local problems would become global problems. It wouldn't be as simple as workers walking out of desperation into paradise: unless something more fundamental and structural changes, there is reason to think the conditions of their exploitation will follow them. Perhaps it is not best to globalize the labor pool before we have figured out how to structure an economy that is fair to the laborer, or we will just globalize and perpetuate our mistakes, our market crashes, and our vectors of oppression. Perhaps it is better to have some isolation between economies so we can run more experiments and find better answers.
But I don't necessarily believe the argument I just gave. I just think it's an angle that needs to be addressed, and that's just one example. I also doubt his view that maximizing wealth is the right goal to have, especially considering the short-sightedness with which economies tend to do this: preferring immediate gains in private share value at the expense of trashing common goods like our natural resources and our atmosphere. Can we confidently say that tossing immigrant coal into the engine of the capitalist machine will maximize human happiness in the long term, after accounting for the potentially catastrophic externalities of climate change?
Given Weinersmith's role in this book, I had assumed (being a fan of SMBC) that some nuanced discussion of these kinds of issues would show up. But given that the real writer seems to be Bryan Caplan, it's no wonder that it's disappointing. You can never trust economists to do the kind of thinking that extends outside of their models, even when their models clearly don't fit the situation.
The sad part is: on balance, I think I might support open borders! Or something very close to it. But this book really made a woeful case.