First, an increase in immigration permanently dilutes the costs of military action. Military expenditures are invariant to the population. Yet, over the long term this is actually a much larger concern than either Social Security or Medicare. As China, India and Brazil industrialize, either the United States will have to drastically increase the percentage of GDP spent on the military or it will have to relinquish its position as a world superpower.
I know that seems like a fine idea to many, especially to many libertarian minded folks. However, liberal democracy has flourished almost entirely under the canopy of Anglo-American hegemony. It is entirely possible that a truly multi-polar world could sustain liberalism but it is not, however, entirely certain. To my mind the maintenance of the Open Society is our primary responsibility and I am not inclined to leave it to chance.
Now let me be clear. I am not an evangelical liberal. I don’t see it as necessary or even in all cases desirable to attempt to spread the basic principles of the Open Society. I do see it, however, as crucial to maintain the Open Society where it currently exists.All emphases in block quotes are his. This is a fascinating point. I think it's an uncomfortable fact that many periods of globalization throughout history have been supported by empire: The Romans, the Mongols, the British, etc. One really hopes that this will not always have to be the case, that we will one day be able to harness the benefits of globalization without needing to suffer the violence of imperialism. In any case it appears impossible to maintain hegemony in perpetuity. In light of this I actually think diluting the cost of the military is an argument against liberalizing immigration because cheapening military action will lead to more ill-considered adventurism, leading to more suffering abroad and loathing of the hegemonic power. Loathing from inevitably rising powers will not help to preserve the Open Society.
But there are clearly countervailing effects of immigration as well. Since Smith pointed out that over 20 million of those 180 million aspiring immigrants are Chinese, I was reminded of one of my all-time favorite Brad DeLong posts:
Think of it this way: Consider a world that contains one country that is a true superpower. It is preeminent--economically, technologically, politically, culturally, and militarily. But it lies at the east edge of a vast ocean. And across the ocean is another country--a country with more resources in the long-run, a country that looks likely to in the end supplant the current superpower. What should the superpower's long-run national security strategy be?
I think the answer is clear: if possible, the current superpower should embrace its possible successor. It should bind it as closely as possible with ties of blood, commerce, and culture--so that should the emerging superpower come to its full strength, it will to as great an extent possible share the world view of and regard itself as part of the same civilization as its predecessor: Romans to their Greeks.
In 1877, the rising superpower to the west across the ocean was the United States. The preeminent superpower was Britain. Today the preeminent superpower is the United States. The rising superpower to the west across the ocean is China. that was the rising superpower across the ocean to the west of the world's industrial and military leader. Today it is China.
Throughout the twentieth century it has been greatly to Britain's economic benefit that America has regarded it as a trading partner--a source of opportunities--rather than a politico-military-industrial competitor to be isolated and squashed. And in 1917 and again in 1941 it was to Britain's immeasurable benefit--its veruy soul was on the line--that America regarded it as a friend and an ally rather than as a competitor and an enemy. A world run by those whom de Gaulle called les Anglo-Saxons is a much more comfortable world for Britain than the other possibility--the world in which Europe were run by Adolf Hitler's Saxon-Saxons.
There is a good chance that China is now on the same path to world preeminence that America walked 130 years ago. Come 2047 and again in 2071 and in the years after 2075, America is going to need China. There is nothing more dangerous for America's future national security, nothing more destructive to America's future prosperity, than for Chinese schoolchildren to be taught in 2047 and 2071 and in the years after 2075 that America tried to keep the Chinese as poor as possible for as long as possible.Immigration is 'blood, commerce, and culture' all at once. Happily, I reckon the illiberal effects of cheaper military aggression are overwhelmed by the formation of peaceful bonds that immigration facilitates.
Second, immigration temporarily dilutes expenditures on Social Security, Medicare, and interest on the national debt. However, temporary counts for a lot. The future is inherently uncertain and so truly pushing off consequences into the future is inherently a net gain. There is a chance of catastrophe, in which case your sacrifices were useless and there is a chance of explosive growth, in which case your sacrifices were unnecessary. These are real possibilities and should not be ignored.True enough. The advantages of a younger society are ample and fairly well known.
It also gives additional time to prepare for changes in Social Security. One possibility is that the continued shift away from physically intensive jobs will mean that in 50 years a retirement age of 70 is feasible even if in 25 years it is not.
Third, the rate of world wide technological progress is likely proportional to the number of people living in countries at or near the technological frontier. Increasing the number of Americans increases the growth of technology generally.This is a favorite of mine, and a point that applies equally to charter cities as to expanding immigration. From a brute counting perspective, a large, dense, well connected population simply affords more opportunities for serendipitous collisions of ideas. Perhaps the analogy is too simple, but likening society to a big brain can be illuminating. A large population has more neurons making possible vastly more neural connections. This is true in any case, including cities in developing countries, but as Smith suggests, it seems likely the innovation generating quality of population density will be even greater if more of those innovators have access to the tools, resources, and institutions of the rich world.
Fourth, immigration is the most effective poverty elimination program known. Not only does it dramatically increase the standard of living of the immigrants but remittances to home countries by immigrants represents a greater transfer of resources than all foreign aid combined.This cannot be shouted from the rooftops loudly enough or often enough. If you are at all concerned with improving the welfare of the world's poorest human beings and you do not support liberalizing immigration, then you have a damn lot of explaining to do.