Since opponents of open borders tend to ask confused questions about it, let’s be clear about what ‘open borders’ actually means. Bear with me, because this will take some time.

What open borders mean

Typically the borders between neighborhoods in a city, between cities in a region or between regions in a state are open. The borders between states in the USA and in the Schengen zone are open too.

Open borders are borders that aren’t patrolled, aren’t fenced or walled off, and crossing them does not result in harsh punishments. If people want to cross those borders to find a better place to work and live, then little or nothing gets in their way.

Open borders don’t mean just letting foreign refugees stay in your country as long as returning to their home country is no option and then helping the ones in need.

Even if you don’t want to coordinate refugee streams with other safe countries and instead let refugees choose where they want to stay, this is far from open borders. So contrary to popular right-wing superstition, most of the left does not support open borders.

Open borders don’t force people to share their house or business with foreigners. In fact, rather than losing the right to keep people off your property, you gain the right to have foreigners on your property no matter what resentments your neighbors may feel for them. If you think this is obvious, then you are smarter than most open border opponents.

Open borders have nothing to do with defending a country against invasions. Generally, invaders commit horrendous crimes against the government and a military reaction is both warranted and needed.

The idea that immigration restrictions are going to hold invaders back is laughable, as it the idea such restrictions would have saved the Roman Empire or Native Americans.

Finally, open borders don’t mean ‘no borders’ and you don’t have to be a social justice warrior to support them.

The case for open borders

I am an open border supporter, but not primarily because I think open borders are a good idea. Instead, my top three reasons are the following.

1. Being born on the other side of a border is no crime and doesn’t deserve any punishment, let alone harsh ones like exile for life.
2. In practice, immigration restrictions hurt millions of the most unfortunate people on Earth: poor people born in poor countries. For many, migrating is the most promising way to improve their lives and the lives of their families. Many are desperate enough to defy our immigration restrictions, even though that means risking being exploited, robbed, enslaved or even getting killed. That is how severely closed borders are hurting people.
3. In practice, immigration restrictions don’t prevent many social problems in wealthy countries. Wealthy countries are at a historical low point for population growth, crime, unemployment, intolerance, etc. Even if letting immigrants come makes things a little worse for us in these areas, this does not justify deeply harming innocent people. To make matters worse, immigration is actually good for economic growth, so we are stupidly hurting ourselves by closing the borders.

If you need more, then go read Open Borders: The Case. Besides giving more arguments for open borders the site debunks many objections as well.

Original question: Why would anyone think open borders are a good idea?

Several advantages off the top of my head:

• Open borders allow people to move to places with less oppressive regimes and open borders create more relations across borders. This encourages finding peaceful solutions to political problems.
• The exchange of ideas between people of diverse backgrounds drives creativity in science, technology, and art, which is ultimately where all progress comes from. Open borders allow more of this exchange.
• Aging populations with excessive entitlements for the elderly are more easily afforded with the helping hands of cheap migrant workers.
• We can eliminate poverty by moving people to the means of production or by building means of production nearer to people. The former has a lower ecological footprint and probably causes less climate change as well.
• Open borders reduce the number of asylum seekers because it gives foreigners an attractive alternative to fleeing or pretending to flee.
• Open borders allow people to move to places where they are most productive. Many people take this opportunity because productive areas are areas where many people enjoy high living standards. The result is a more economically efficient distribution of people over the world.