1. When Noah describes the economic benefits of immigration, he makes it sound redistributive: Our GDP goes up because we gained people, which presumably means the sending countries' GDP goes down by the same amount because they lost people. At least that's the natural way to read this passage:
The way to get 4 percent growth is open-borders immigration policy.
Gross domestic product is simply the product of output per person and
the number of people. The more people in your country, the higher the
output. That's why China, whose output per person is only about a
quarter of the U.S.'s, is now the largest economy on the planet. It just has more bodies.
growth numbers you usually hear about in the news are total GDP growth
numbers, not per capita figures. To boost those numbers, get more
population. For example, when Great Britain conquered India, the GDP of
the British Empire went way up. If the U.S. really wanted to supercharge
its GDP numbers, it has a much better option than military conquest --
it could simply invite tons of immigrants to move here.
2. Noah generously hands me some free publicity, but what he says isn't quite right.
Exactly this sort of open borders immigration policy has received enthusiastic support
from a dedicated core of libertarian economists, notably Bryan Caplan
of George Mason University. These economists believe in relaxed
immigration rules not because they want higher GDP growth, but because
of principle -- they view national borders themselves as an unacceptable
form of government intervention in the economy.
The open borders
crusaders are so zealous that moderate supporters of increased
immigration, such as tech entrepreneur Vivek Wadhwa, are often the targets of their ire. University of Chicago economist John Cochrane has also voiced support for the open borders idea.
Example: Suppose initially, a country has 100% high-skilled
natives earning $40,000 a year. Low-skilled foreigners earn $1000 a
year in their home countries. After open borders, the U.S. population
shifts to 50% high-skilled natives earning $50,000 a year, 50%
low-skilled foreigners earning $10,000 a year. All individuals are
richer. But U.S. per-capita GDP just fell from $40,000 (1*$40,000) to $30,000 (.5*$50,000 + .5*$10,000).