The practice of granting citizenship to every child born inside a country’s border stretches far back in history. In recent years however countries that once viewed citizenship a matter of jus soli, or a “right of the soil,” have changed their minds. When Ireland amended its constitution in 2004, for example, it meant that unconditional jus soli stopped being law in any European country. Australia made a similar change in 1986. These and other societies now generally require that at least one parent be a citizen, permanent or long-term legal resident. (Australia also grants citizenship to children of non-citizens if the children live there until age ten.)

The Conservative Party of Canada recently called for Canada to make a similar switch. Our current practice is to grant citizenship to practically all children born on domestic soil (those born to diplomats and other employees of foreign governments are an exception). At their August convention in Halifax the Conservatives resolved to “fully eliminate birthright citizenship in Canada unless one of the parents of the child born in Canada is a Canadian citizen or permanent resident.”

Debate over Canada’s citizenship laws has been set off by media reports of “birth tourism,” a phenomenon of foreign mothers-to-be who come to Canada to deliver their baby, thereby allowing the child to obtain citizenship without having to apply for it. Critics point to the practice to argue that jus soli is a holdover from feudalism, no longer relevant in the modern world. This however only shows that feudal conceptions of belonging are underrated. Alternative approaches may sound nice in theory but they have grim consequences in practice. Jus soli is a crude and simplistic approach to citizenship, but rather than a drawback, that is its strength. The international trend against it is one Canada should resist.

Canadians need proof of citizenship in order to obtain a passport or register to vote. Right now the way to provide that proof is simple: produce a birth certificate. As the B.C. Civil Liberties Association has noted, abolishing jus soli means that the government will have to come up with some other way of verifying citizenship. One possibility would be the introduction of a national identity-card system, estimated to cost billions of dollars. Whatever the new arrangement turns out to be, it is likely to be more cumbersome than the system now in place. Ironically, the Conservatives’ proposal would ­create more government bureaucracy and oblige Canadians to fill out more tedious paperwork, outcomes that conservatives normally oppose.

There is a deeper problem. It can be seen by considering the American experience with jus soli. The U.S. constitutionally enshrined the principle in the 1860s. Prior to this time greater government discretion over who was a citizen saw African-Americans and Indigenous people targeted by laws that systematically denied them citizenship. Even after jus soli laws were on the books, the country experienced moral panics that saw it compromise its commitment to universal citizenship for the native-born. A 1907 measure for example, memorably known as the Gigolo Act, said that American women who married foreign men took on their nationality, and were no longer Americans. U.S. writer Jeffrey Rosen has summed up the American experience, the consistent application of jus soli “has been a friend of oppressed minorities throughout our history, while the competing traditions, in which citizenship descends by blood, or naturalization is based on mutual consent, have been malleable tools of nativists and racists.”

Why might a descent-based approach to citizenship be a “malleable tool” of exclusion? The answer can be seen through a comparison to the legal concept of hate speech. One of the original ideas behind hate speech was to penalize speech that “promoted hatred” toward racial minorities and other traditionally disadvantaged groups. Critics however, including many conservatives, have long suggested that the concept of hate speech has experienced the conceptual equivalent of mission creep: it gets applied far beyond its intended purview. A recent controversy at the City University of New York for example involved a student who denounced scholarships to Israel as “sick Zionist propaganda.” He became the subject of a formal investigation after another student objected that “this is hate speech.” The student’s remark about scholarships was intemperate. But did it really generate hatred in people who were exposed to it?

Hate speech is notoriously difficult to define. The approach to citizenship that considers it a matter of jus sanguinis, or a “right of blood,” meanwhile, is not. But what the two notions have in common is that they both establish a fateful precedent. The concept of hate speech legitimized the idea that some speech should be penalized simply because of how prejudicial it is. Is it any surprise that people began to deploy the concept against views they detested? Similarly, jus sanguinis legitimizes the idea of significant numbers of people being born in Canada without becoming citizens. That idea is even more ripe for abuse. It is one reason why Japan, Kuwait, and other countries that have descent-based approaches to citizenship also have permanent disenfranchised populations.

Of course if Canada abolished jus soli it is unlikely to result in the same patterns of exclusion as Japan or Kuwait, let alone nineteenth-century America. But nativism and racism are hardly consigned to history. In Canada’s current climate, native-born Muslims who run afoul of the law—and perhaps even some who do not—would be at heightened risk of being stripped of their ­citizenship.

The unthinking inclusiveness of our current approach to citizenship means that we don’t go near that possibility. In this way the case for abolishing jus soli is ultimately a bit like the case for making the right to vote conditional on demonstrating political knowledge. In theory a test that would weed out low-information voters has some appeal: populist demagoguery would be less effective. In reality, whenever lawmakers have made voting rights conditional on literacy or similar tests, the tests have been administered in unfair, often racist ways. An inclusive policy regarding whose babies get citizenship, like an inclusive policy regarding who can vote, means we avoid the possibility of abuse or the risk of citizenship eligibility being narrowed still further beyond what the Conservatives have proposed. To think Canadian lawmakers can avoid these temptations requires a naive faith in their ability to apply the law with Solomonic detachment. That kind of utopianism conservatives are also supposed to oppose.

There is something unreal about jus soli coming up for re-examination in 2018. No one really knows how many pregnant mothers come to Canada just to have the baby. Statistics Canada says that in 2016, 313 children were born across the country to non-resident mothers. Critics say the real number is three times that official count. Suppose they are right. That is still less than a thousand births a year, or just over a quarter of one per cent of the 383,102 births Canada saw in 2016. This is a baby problem in more ways than one.

The fixation on current births however is bizarre by itself. Canada has implemented some form of jus soli since 1947. If the law itself were the problem, critics should be able to point to people currently 18 or older who are unfairly enjoying the benefits of citizenship because their mothers snuck into the country years ago to give birth. It is noteworthy that no one ever cites such people. It is also noteworthy that we are not debating regulating birth tourism or other more targeted measures that would not call into question the country’s commitment to inclusion and equality before the law. If we believe in those things, jus soli is a line we will always draw in the soil.

Andy Lamey teachers philosophy at the University of California at San Diego and is author of Duty and The Beast: Should We Eat Meat in the Name of Animal Rights?, forthcoming from Cambridge University Press.

Related Letters and Responses Andy Lamey is right not to trust politicians to adjudicate fairly a more discretionary ­citizenship policy than jus soli. Just see how Conservative and Liberal governments alike have treated Canadian citizens like Maher Arar, Abousfian Abdelrazik, and Omar Khadr (who was born in Toronto) when it suited their cynical purposes. Still, were the policy passed at the Conservative convention in August implemented, Canada would join every comparable nation save the United States—a lodestar Canada normally sails away from rather than toward—in placing restrictions on birthright citizenship. Further restrictions, that is. It seems to be entirely uncontroversial...