Today is Open Borders Day – an international event created to celebrate the ideal of freedom of movement across international boundaries. Open borders is a radical principle, but also one deeply rooted in American history and in widely held liberal values of liberty and happiness. Allowing free movement across borders would greatly increase individual freedom, and allow millions to escape poverty and oppression. The struggle for free migration is one of the most important human rights issues in the world today.

The open borders ideal does not require complete freedom of movement. It does not, for example, require national governments to let in terrorists, invading armies, or carriers of deadly contagious diseases. It does require that your migration rights should no longer be restricted merely based on the fact that the you were born on the wrong side of a line on the map.

I. The Case for Open Borders.

Hundreds of millions of people live in countries where their probable fate is a life of poverty and oppression. Many of them could escape that terrible fate if only First World governments would allow them to immigrate. Economist Michael Clemens estimates that the economic gains from worldwide open borders are large enough to double world GDP. Enormous numbers of people currently live in poverty not because they are unable to be productive workers, but merely because they are forcibly prevented from working for First World employers who would be willing to hire them. In addition to harming potential migrants, these restrictions also inflict losses on First world employers, landlords, and consumers who would like to hire immigrants, rent to them, or purchase goods and services they produce.

But the benefits of open borders go far beyond purely material gains, great as they are. Many potential migrants are also trapped in societies where they are denied basic human rights, such as freedom of speech, religion, and private property. Many of the women among them reside in societies with severe gender-based oppression and discrimination. For hundreds of millions of people living in undemocratic societies, emigration is their only realistically feasible way to exercise political freedom – the right to choose what kind of government they wish to live under.

Perhaps most important, immigration restrictions are severe infringements on individual freedom in and of themselves. They forbid people to live and work where they wish purely based on arbitrary circumstances of birth for which they are not responsible. They also restrict the liberties of native-born citizens who wish to engage in economic and social transactions with migrants.

Some argue that First World governments are not responsible for the poverty and oppression that exists in Third World countries, and therefore we have no moral obligation to let in immigrants fleeing from it. But when we restrict immigration, we do more than simply ignore poverty and oppression created by others. We actively use the threat of force to prevent immigrants from escaping those terrible conditions.

While open borders would be a radical change from current policy, it is an ideal deeply rooted in the American political tradition. The original meaning of the Constitution denies Congress the power to restrict international migration, though it does give it the power to control naturalization. The United States in fact had virtually complete open borders until the enactment of the racist Chinese Exclusion Act of 1882, and open borders for nearly all non-Asian immigrants until the 1920s. If today’s more restrictionist policies had been followed in the first 130 years of American history, the ancestors of most Americans would never have been allowed to enter the country.

Moving towards open borders would allow the United States to again become what Ronald Reagan called “a promised land… [where] any person with the courage, with the desire to tear up their roots, to strive for freedom, to attempt and dare to live in a strange and foreign place, to travel halfway across the world was welcome here.” Even under current restrictive policies, the US and other Western democracies have taken in numerous immigrants who would otherwise have suffered a much worse fate – myself included. But we still fall far short of the ideal Reagan so eloquently expressed.

II. The Burden of Proof for Justifying Migration Restrictions.

There is a wide range of objections to free international migration. But nearly all of them are either inaccurate (such as the claim that immigration increases welfare spending), or can be addressed through less draconian means than consigning millions of people to lives of poverty and oppression. For example, there are lots of more humane ways to control “political externalities” – possible negative effects of immigration on government policy.

Most importantly, any negative effects of immigration must be weighed against the truly enormous benefits – in terms of both freedom and happiness. In order to justify migration restrictions, the harms they prevent must be both large enough to outweigh those benefits and impossible to prevent by less repressive means.

Like other important individual liberties, the right to free migration cannot be absolute. Just as there are extreme situations where we might be justified in restricting freedom of speech or freedom of religion, so too there are extreme situations where immigration restrictions would be justified. But just as restrictions on other important freedoms should meet a high burden of proof, the same goes for immigration restrictions that use the threat of force to compel people to live in poverty and oppression. At the very least, we must demand strong evidence that the restrictions prevent real harms large enough to outweigh the benefits of free migration – including the benefits for the rights and freedom of immigrants themselves. Open Borders Day is an excellent time to seriously consider whether our present immigration policies even come close to meeting that burden.