Explanations for the concentration of birthright citizenship in the Americas range from European colonial powers establishing lenient laws to attract immigrants and displace native populations in the New World to Latin American independence movements that embraced a more expansive definition of citizenship as part of their rejection of slavery in the 19th century. (The Fourteenth Amendment, adopted in 1868, likewise conferred citizenship on freed slaves in the United States.)

The practice has at times come under assault in Latin America, where rates of immigration are relatively low; birthright citizenship was retracted in 1978 under Argentina’s dictatorship, for example, only to be restored when democracy returned, in 1983. But it has proved more controversial in Canada and especially in the United States, which attract larger flows of immigrants and in recent decades have grappled with an influx of illegal immigration.

Just as Trump rails against undocumented immigrants having “anchor babies” in the United States that allow them to settle in the country through their citizen children, conservative politicians in Canada have condemned “birth tourism.” The opposition Conservative Party vowed last summer to pursue legislation to eliminate birthright citizenship unless one of the parents of the child born in Canada is a citizen or permanent resident. Opponents of the move claimed that the birthright provision in the country’s 1947 Citizenship Act is central to Canadian conceptions of equality and multiculturalism.

Countries That Used to Have Birthright Citizenship but Don’t Anymore

The U.S. wouldn’t be the first country to revoke jus soli, or the “right to the soil,” as birthright citizenship is commonly known.

France did away with birthright citizenship in 1993, following the passage of the Méhaignerie Law. The law limited citizenship to those born to a French parent, or to a parent also born in France. As a result, those born in France to foreign-born parents must wait until they turn 18 to automatically acquire French citizenship (a process that can begin when they turn 13, if they apply).

Ireland was the last of the European Union countries to abolish birthright citizenship, in 2005. Through a referendum backed by nearly 80 percent of Irish voters, citizenship was limited to those born to at least one Irish parent. The decision was a response to a controversy surrounding birth tourism and the high-profile case of Man Levette Chen, a Chinese national who traveled to Northern Ireland so that her daughter would be born an Irish citizen. Chen sought residency rights in Britain, citing her child’s Irish and EU citizenship. Though the United Kingdom Home Office rejected Chen’s application, the decision was overturned by the European Court of Justice in 2004.

Other countries, including New Zealand and Australia, have also abolished their birthright-citizenship laws in recent years. The latest is the Dominican Republic, whose supreme court ruled to remove the country’s birthright laws in 2013. The decision retroactively stripped tens of thousands of people born to undocumented foreign parents of their citizenship and rendered them “ghost citizens,” according to Amnesty International.