Immigration policy – and in particular what to do about the 11 million people in the U.S. illegally – is the new litmus test for the GOP. The arguments over “amnesty” and border security are stale, but the passions are not.

Scott Walker is only the latest candidate to stumble over the immigration tripwire. Though previously supportive of providing a path to citizenship for undocumented residents, now the Wisconsin governor is talking up border security. Advice to candidates: maybe it’s time for some new policy ideas, like demanding an end to our so-called “birthright citizenship.”

Among developed nations, only the U.S. and Canada still offer automatic citizenship to children born on their soil. Not a single European country follows the practice. We take this right for granted, but the evidence is that this entitlement encourages a booming birth tourism business (which undermines our immigration objectives) and virtually guarantees that the number of people in the country illegally will continue to grow.

Related: Obama’s Immigration Setback Is a Gift to the GOP

Federal agents recently raided 37 sites in southern California, which appear to have provided thousands of Chinese women the chance to give birth to babies on U.S. soil in exchange for fees of up to $60,000. Enticements included not only the opportunity to acquire automatic citizenship for their children – a package of free schooling, food, health and retirement benefits potentially worth millions of dollars – but also more mundane attractions like nannies, trips to Disneyland and fancy restaurants.

The New York Times notes that affidavits filed by law enforcement authorities “quote Chinese government sources as reporting that Chinese nationals had 10,000 babies in the United States in 2012, up from 4,200 in 2008.”

For prosperous Chinese or residents of unstable countries like Russia, an American passport represents an invaluable safety net. Some estimate that as many as 40,000 children from all over the world are born under such circumstances in the U.S. each year. Over time, with family members climbing aboard, the total allowed into the country multiples.

Once those babies turn 21, and if they are in the country, they can sponsor other family members to enter the U.S. Under our law, which promotes family unification, parents, siblings and minor children of a U.S. citizen are welcome. According to a report from John Feere of the Center for Immigration Studies, admitting family members account for most of the nation’s growth in immigration levels. Of the 1,130,818 immigrants who were granted legal permanent residency in 2009, a total of 747,413 (or, 66 percent) were family-sponsored immigrants.

Related: Study Finds Illegal Immigrants Pay 11.8 Billion in Taxes

The commercial exploitation of our laws is repugnant and should be targeted. But the entire notion that any baby born on U.S. soil should become a citizen should be challenged as well. The lure of U.S. citizenship is incalculable, and has long encouraged illegal immigration. In a phone interview, Feere estimates that some 300,000 to 400,000 babies are born each year to people living in the country illegally. Pew puts the figure at 340,000. This obviously causes substantial growth in the undocumented population, which most would like to limit.

Critics of the “amnesty” being offered to millions of undocumented persons by President Obama say that the offer will only encourage more illegal entrants – and entice even more families to have babies in the U.S. Obama’s plan provides protection against deportation for three years, and singles out the undocumented parents of U.S. citizens and legal permanent residents who have lived in the country for at least five years.

Some 4 to 5 million immigrants fall under that umbrella, people who had children once inside the country -- children who automatically became U.S. citizens. Advocates of immigration reform need to convince opponents that they will reduce the number of undocumented persons entering the country. While many preach border security, it would be more powerful to make illegal residency less attractive. Revoking the birthright citizenship would be a good start.

Immigration advocates argue that automatic citizenship is protected by the 14th amendment of the Constitution, which states, “All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the state wherein they reside.” Others say the history of that amendment suggests otherwise; the debate hasn’t stopped legislators from attempting to limit the practice.

Related: Obama’s Action Gives Illegal Immigrants Billions in Tax Credits

The first such attempt was in 1993, at the hands of none other than immigrant advocate Harry Reid, whose bill would have restricted automatic citizenship to the children of U.S. citizens and legal resident aliens. Today, Louisiana Senator David Vitter is set to propose an amendment restricting the automatic citizenship provision to babies born to a U.S. citizen or a person who is a permanent resident or serving in the military. This would seem a reasonable change in the current law.

Like so many policy debates, the issue of birthright citizenship may eventually land in the lap of the Supreme Court. Feere says that while there have been rulings that grant citizenship to the children of permanent resident aliens, there has been no decision on the children of temporary aliens – such as people visiting legally on a student visa – or on babies born to illegal immigrants.

Astonishingly, the government, which Feere describes as being on “automatic pilot” on this issue, even gives passports to children born to foreign diplomats here – clearly people not “subject to the jurisdiction” of the U.S. When he followed up with the Social Security Administration on this question, he was told they knew the practice was inappropriate, but were not sure how to monitor it. Sigh.

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