Refugees walk through a field after crossing from Serbia to Hungary, in Roszke, Thursday, Aug. 27, 2015. Over 10,000 migrants, including many women with babies and small children, have crossed into Serbia over the past few days and headed toward Hungary. (Darko Bandic/Associated Press/AP)

Are the Syrians flooding Europe’s shores migrants or refugees? The answer is not just semantic; it can be a matter of life and death. States are required not to send refugees back to persecution. Migrants can legally be shipped back to the horrors they fled.

What is a refugee?

Under international law, a refugee is a person who has fled her country based on a well-founded fear of persecution on the basis of race, religion, nationality, political opinion, or membership in a particular social group. States—even those who are not parties to the 1951 Convention Relating to the Status of Refugees—may not send refugees back to danger. Parties to the treaty are required to give refugees other basic rights like access to courts and to education, which can be expensive.

International law thus protects a very narrow group of people. To make it even harder to enter their countries, most Western states will only grant refugee status if applicants can prove that they have a very specific fear of persecution. This is hard for people who run for their lives, especially if they didn’t have time to grab identity documents from their safe deposit boxes.

Despite how difficult it is to prove refugee status, the U.N. Refugee Agency had classified 13.6 million people in the world as refugees as of 2014.

More than 41.2 million other people are “of concern” to the U.N. Refugee Agency, including the so-called Mediterranean “migrants.” These people have little to no international legal protection. Most international human rights law treaties merely require states to protect the rights of their own citizens. The Convention Against Torture requires that states cannot return a non-citizen to a place where there is reason to believe he would be tortured, which is again a high burden of proof.

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“Migrant” lets nations off the hook

But the term “migrant” itself has no meaning in international law, although The International Convention on the Protection of the Rights of All Migrant Workers and Their Families does protect “migrant workers” who have jobs abroad. The word “migrant” is commonly used to refer to anyone coming to another country to seek work, refuge, escape from war, or otherwise. By using the term “migrant” and lumping these groups under it, public figures and the media imply that Europe owes them nothing.

Many Syrians fleeing to Europe would not qualify as refugees under international law, and therefore can be deported home. Flight from generalized violence and war is not enough to claim refugee status.

Yet as a moral and political issue, their claims for international assistance are far stronger than those of economic migrants. For this reason, the EU has directed its member states to grant temporary protection to people who do not qualify for refugee status if they have a substantial reason to fear death, torture, or serious harm if sent home. But many member states have not followed the EU directive. Many have little incentive to do so, with widespread public backlash against migration, right-wing governments elected partially on anti-immigration platforms, and economic troubles of their own. To be sure, taking migrants in temporarily or permanently would constitute an economic and political burden. The vast majority of migrants smuggled to Europe, the U.S., or elsewhere have no legal protection from being sent home. Mass deportation of millions would be inhumane—but could be perfectly legal.

New international law is needed

What is to be done? We need new international law to assure states that they can still police their borders while protecting the human rights of those who seek to enter. European ministers will meet on Sept. 14 to explore new tools to stem the crisis. But Europe cannot solve the migration crisis alone—and it should not have to.

The Mediterranean exodus is only one part of a global migration crisis. This mass migration is a cause and effect of global instability. Historically, states have made new law to protect displaced people to reflect changing security interests. With migration again threatening the international order, it is time for a new international treaty to protect state interests (for an outline of such a Displaced Persons Convention and analysis of its history, see my working paper, “Displaced: Why We Need New International Law to Protect Refugees, Displaced People, and Human Rights.”

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At minimum, the international community must clarify which migrants it will assist, and how. Uniformity and clarity in asylum procedures in Europe and elsewhere would help states’ and individuals’ behavior, improving security for both.

Clarity is crucial: If migrants knew with certainty that they could not stay in Europe, many would likely seek alternate solutions before leaving. New international law could require, for example, the global North and South to cooperate to address the causes of mass migration, to ensure safe zones for displaced people and measures to prevent population displacement in  conflict zones, and to share the burden of providing migrants with temporary protection.

International law alone will not solve the migration crisis. But changing international law would go a long way toward relieving human suffering. No matter what one calls desperate, fleeing human beings, international law should treat them with dignity.

Jill Goldenziel, J.D., Ph.D., is a research fellow at the Belfer Center for Science and International Affairs at the Harvard Kennedy School and a senior fellow of the Fox Leadership Program at the University of Pennsylvania. She is writing a book about refugees, international law, and U.S. foreign policy.