Yes and no to Alex Tabarrok's Atlantic essay on immigration

Alex Tabarrok has an interesting short essay up at The Atlantic in which he argues for increasing the number of high-skilled immigrants who get to stay. He calls it the "no brainer" of the year. He puts it the following way:

Behind Door #1 are people of extraordinary ability: scientists, artists, educators, business people and athletes. Behind Door #2 stand a random assortment of people. Which door should the United States open?

In 2010, the United States more often chose Door #2, setting aside about 40,000 visas for people of extraordinary ability and 55,000 for people randomly chosen by lottery.

To which I say: yes and no. Yes to increasing legal immigration for high-skilled immigrants, for all of the reasons that Tabarrok sets forth in the piece. But I'm less confident that the dichotomy set up in the first paragraph is the best way to frame the issue generally. It's not obvious to me that the national economy's best served by creating an immigration policy that focuses on getting the most intellectually talented people possible, for the reasons that Tabarrok's GMU colleague and fellow econ blogger sketches out rather colorfully in in part of a blog post that is on the whole about quite a different topic:

Suppose we have an isolated society in which everyone is a genius. Let's call them the Brains. Who takes out the garbage? A Brain, obviously. Who does the farming? Again, Brains.

Now what happens if the geniuses come into contact with a society where everyone is of average intelligence at best? Let's call them the Brawns. If the Brains allow the Brawns to join their society, the average genetic quality of the Brains' society plummets. But everyone is better off as a result! Now the Brains can specialize in jobs that require high intelligence, and the Brawns can take over the menial labor. Total production goes up.

This is an example of what economists call the Law of Comparative Advantage. Trade between two people or groups increases total production even if one person or group is worse at everything. Suppose, for example, that Brains can make 5 Computer Programs or 10 Bushels of Wheat per day, and Brawns can make .1 Computer Programs or 5 Bushels of Wheat per day.

Computer Programs Bushets of Wheat
Brains 5 10
Brawns .1 5
Brains and Brawns can still trade to mutual benefit: Just have one Brain switch from farming to programming (+5 Programs, -10 Bushels of Wheat), and three Brawns switch from programming to farming (-.3 Programs, +15 Bushels of Wheat), and total production rises by 4.7 Programs and 5 Bushels of Wheat.

So I'm not convinced that the United States wouldn't be made better off by letting in additional people who are more like Bryan's imaginary Brawns than his imaginary Brains. Nor am I sure that any government central planner could come up with the right formula to figure out the optimal number of Brains and Brawns to whom to grant visas. It's probably much better to just let as many Brainws and Brawns who think that they can find work to come (so long as neither Brawns nor Brains are terrorists, spies, or have other such problematic skeletons in their closets that would make them obviously poor candidates for eventual citizenship.)

Perhaps Tabarrok thinks that increasing the number of high-skilled immigrants is a more politically feasible reform to current immigration policy than one that would increase legal immigration more generally. If so, fine. But his first two paragraph are still a less than helpful way of framing the issue.