(Joshua Roberts/Reuters)

The 14th Amendment states that “all persons born . . . in the United States, and subject to the jurisdiction thereof, are citizens of the United States.” Despite some debate over the meaning of the words “subject to the jurisdiction thereof,” this has long been interpreted to mean that when an immigrant gives birth here, the child is automatically granted U.S. citizenship, regardless of the strength of the immigrant’s ties to this country and even whether the immigrant is here legally.

One consequence of this rule is “birth tourism”: pregnant women visiting the U.S. for the sole purpose of giving birth, so that their children will have U.S. citizenship, complete with the ability, years later, to sponsor additional relatives for citizenship. The State Department has announced a new rule aiming to cut back on this practice, not by changing the Constitution in any way, but by refusing to grant visas in cases where this abuse seems particularly likely. The rule is sensible, though its effects may be limited.

The policy pertains to temporary “B” visas, which are granted, for example, to tourists and those seeking U.S. medical care. In essence, the new rule says that birth tourism doesn’t count as traveling for “pleasure” under the relevant statute, and directs consular officers to determine whether birth tourism is the primary purpose of a visit. These officers have been instructed not to ask women if they are pregnant “unless you have a specific articulable reason to believe they may be pregnant and planning to give birth in the United States” — but when there are signs that birth tourism is afoot, the burden will fall on the traveler to prove a different reason for the trip.

The rule still allows pregnant women to come for the purpose of giving birth in U.S. hospitals for medical reasons, so long as they are doing so because of the quality of care and proximity to their home countries — and didn’t, for example, select the U.S. over another destination because doing so would win the child citizenship. Those seeking B visas for medical reasons will also have to demonstrate that they have arranged for care and can pay for it.

This addresses a real, if hard to quantify, problem. Some companies openly advertise birth-tourism services abroad, and there have been numerous cases in which providers of these services have resorted to fraud and other illegal activities. The Center for Immigration Studies estimates births to women on tourist visas at 33,000 annually; the new rule, less precisely, says “thousands” of women on B visas give birth here every year.

The main problem with the rule is that it may not prove very effective. Like much of our immigration policy, it depends on consular officers’ asking hard questions and judging the truthfulness of the replies, and as the New York Times notes, “some visas allow foreigners to visit the United States multiple times over the course of as many as 10 years, so an applicant could be granted a visa, get pregnant years later and still be permitted to visit the country.” Further, this will of course not affect travel outside the realm of B visas, including by those who come into the country illegally.

It will take a lot more than this to put much of a dent in the practice of birth tourism. But as far as the rule goes, it’s entirely correct: If the primary purpose of someone’s visit is to give birth in the U.S. and gain citizenship for the child, that person should not be given a B visa.