I enjoy idle speculation, and like many libertarians I like to speculate on the following question: If you could make one big change, what would it be? In other words, what’s the real big issue.

I’m increasingly convinced that the one big issue is immigration. If we opened borders internationally, world GDP would increase by an estimated 50-150%. World income would double! That’s incredible. All those people living on $2 per day would suddenly by doing significantly better if they could only be allowed to work for you!

And the benefits don’t stop there! Gains from trade! By now we all should understand that if I work for you it’s because I value my wages more than my time and you value my time more than the wages (and payroll taxes, and administrative costs) that you pay in order to hire me. So by letting poor people into America they gain by making their employers better off. Their employers are made better off by making their customers better off. You and I are those customers.

So why isn’t this already happenings. There are three basic oppositions.

They’ll use public services without paying taxes. They’ll depress wages and steal jobs They might be dangerous. Either because they’ll commit crimes, or they’ll vote for stupid things (like restricting immigration).

I’m not including a more traditional reason for opposing liberalized immigration: xenophobia and racism. Xenophobia makes sense from the perspective of evolutionary psychology, but it’s not a legitimate reason, and it’s one we can choose to be bigger than.

Okay, so point one, simple solution: give anyone who wants one a work visa. Problem solved. Anyone can come here, but nobody is automatically eligible for public services. They’re above board, on the grid, we can see them, and if they commit crimes they’re out. But they’re obliged to pay into a system that they can’t exploit.

Point two: empirical evidence is that the only group in America genuinely negatively affected are high school dropouts. Want to increase high school graduation rates? Increase the cost of dropping out by letting in immigrants. Everyone else is made more productive because immigrants have different skills than natives, creating opportunities for gains from trade. They are complementary to us, and so make us better off by working along side us. Imagine a lone man on an island. He’s a baker. If he meets another marooned baker, it’s nice, but not as nice as if he meets a marooned butcher.

Point three: first off, getting rid of illegal immigration will make it easier to keep people safe from the foreign menace. Second, immigrants currently have lower incarceration rates than natives. Besides, it’s cheaper to punish them: just deport criminals. No feeding, sheltering, and clothing them; just ship them off. For voting: again, just give them a worker’s visa that doesn’t let them vote.

So what’s the takeaway? A simple policy of letting people come into the U.S. to live and work will make nearly everyone better off, especially the world’s desperately poor. America’s poorest (high school drop outs) may suffer, but there are fairly simple ways to address that. Here’s one: use a slice of the tax revenue from the new immigrants to pay for GED’s, and a stipend to give these folks time to study and pass the test. If they aren’t willing to do that, then that’s on them. If they have some disability that prevents it (maybe they dropped out because of undiagnosed learning disorders), then address those problems, because with that increased tax revenue we can afford to. And anyone born after 1999 is responsible for graduating high school and will be told the costs of failing to do so.

What do we get out of it? International poverty reduction, local wealth increase, a more cosmopolitan society, and a better, more humane world.