I’ve been wondering recently whether I’m simply a hypocrite. After all, I think the world was wrong to close its doors to Jewish refugees during the Nazi era, yet I sympathize with the West’s unwillingness to welcome the seemingly endless stream of desperate people beating on its doors today. So in an effort to determine whether my position has any conceivable justification, I finally read the U.N. Refugee Convention of 1951, the foundational document codifying the international obligation to help refugees.

The popular view of this convention is that it protects anyone fleeing genuine danger. Moreover, that’s how many countries seem to have interpreted it in practice. Yet its plain language is far more restrictive than that—so much so that it would arguably exclude most of today’s migrants. And there’s a very good reason for this. But before considering the reason, let’s consider what the convention does and doesn’t say.

Its definition of a refugee has two clauses. The first covers specific groups defined as refugees under previous conventions—victims of the Nazis, Armenian victims of Turkey’s genocide, Russian victims of the Communist regime. The second covers anyone who has a “well-founded fear of being persecuted for reasons of race, religion, nationality, membership of a particular social group or political opinion, is outside the country of his nationality and is unable or, owing to such fear, is unwilling to avail himself of the protection of that country; or who, not having a nationality and being outside the country of his former habitual residence as a result of such events, is unable or, owing to such fear, is unwilling to return to it.”

That definition has several surprising omissions. Most notably, it never mentions war, though anyone in a war zone obviously faces real and life-threatening danger. This danger, however, doesn’t usually stem from persecution based on race, religion, etc.; rather, it’s inherent in the nature of war, affecting everyone in the area where bombs and bullets are flying. Thus people fleeing war zones seemingly wouldn’t be covered by the convention’s plain text, unless they’ve also been specifically targeted due to race, religion, etc.

Another glaring omission is dictatorship. Though dictatorships do oppress people on the basis of race, religion, etc., many also practice forms of repression that affect all their citizens, rather than targeting specific groups or individuals; think North Korea or Eritrea. Yet according to the convention’s plain text, simply living in an oppressive dictatorship wouldn’t entitle someone to refugee status, unless he were also specifically targeted due to race, religion, etc.

The third noteworthy omission is dysfunctional governments, which are incapable of protecting their citizens. That’s the problem for many of today’s Latin American émigrés, who are fleeing horrific gang violence that their governments can’t seem to stop. Again, the danger that they’re fleeing is real and life-threatening. But the gangs usually don’t target people due to race, religion, etc.; they tyrannize indiscriminately. Hence according to the convention’s plain text, most of their victims also wouldn’t be entitled to refugee status.

If the popular view of the convention were accurate, then it would apply to anyone fleeing war, dictatorship or dysfunctional government since all such people are genuinely endangered. But it’s no oversight that the convention doesn’t cover any of these cases; in fact, it was crafted so narrowly for a very good reason.

The reason is that international law is not a suicide pact. Indeed, it can’t be, because no country would sign an international convention whose terms, if honored, would undermine the country’s well-being. In this case, no country would have signed a convention requiring it to open its doors to a virtually unlimited number of migrants because there are limits to how many people any country can absorb without causing social upheaval.

The expansive definition of “anyone fleeing real danger” would comprise hundreds of millions or even billions of people. If anyone fleeing war were a refugee, for instance, then over the past few years alone, the entire populations of Syria, Afghanistan, South Sudan, Somalia, Central African Republic and Iraq would have been entitled to refugee status—and that’s not even an exhaustive list. If anyone fleeing a dictatorship or dysfunctional government were a refugee, the world would have to open its gates to the populations of much of Africa, central Asia and Central America. And as the current backlash to immigration in both America and Europe shows, this is simply more than most countries will ever be willing to do.

Hence the convention’s drafters were careful to choose an inherently limited definition. Groups being persecuted due to race, religion, etc. are almost always comparatively small minorities that the world could manage to absorb—Jews under the Nazis, Yazidis under the Islamic State, Rohingya in Myanmar, and so forth.

Moreover, people targeted on the basis of race, religion, etc., are often the very people most in need of refuge. And if the world can only absorb a limited number of refugees, it makes sense to give priority to those most in need.

The problem with expanding the definition of refugees beyond the convention’s narrow bounds isn’t just that it violates the convention’s plain text, although that’s a danger in itself: If conventions end up entailing obligations far beyond those to which the signatories originally consented, then countries will eventually refuse to sign any convention at all.

The other danger, however, is that if everyone is considered a refugee, then in the end, nobody will be. If refugees are a limited class of people, there’s some hope that other countries can be persuaded to take them in. If they’re an infinite class of people, then ultimately, the world will shut its gates to them all. Indeed, some countries are already doing just that.

The desire to expand the refugee definition is motivated by real concern for people in real danger. But this is a classic case in which, as Voltaire famously said: “Perfect is the enemy of good.” In the real world, only by retaining a narrow definition of refugees will we be able to preserve any protections at all, even for those who need them most.

Evelyn Gordon is a journalist and commentator living in Israel.