Washington, April 2 : The US government flagged concerns over â??birth tourism,â?? particularly from China, as it urged the Supreme Court to curb automatic citizenship for children born on American soil.

Arguing for the Trump administration, Solicitor General John Sauer told the court on Wednesday (local time) that foreign nationals are increasingly travelling to the US to give birth, creating what he described as a large-scale industry.

He cited reports of up to 1 to 1.5 million births linked to Chinese nationals and said there were hundreds of companies in China facilitating such travel.

Sauer said the current system makes the United States an â??outlier among modern nationsâ?? and acts as a pull factor for immigration.

He told the court that â??every nation in Europe has a different rule,â?? with most countries tying citizenship to parentage rather than birthplace.

The argument brought a geopolitical dimension to the constitutional case, which centres on whether the 14th Amendment guarantees citizenship to nearly all children born in the US.

Several justices questioned whether international comparisons should influence constitutional interpretation.

Justice Brett Kavanaugh stated that global practices may be relevant for policy debates but not necessarily for interpreting US law.

Opponents of the administrationâ??s position made a similar point, arguing that the Constitution reflects a uniquely American approach rooted in history.

They said the 14th Amendment was designed to create a clear rule: birth in the United States confers citizenship, with only narrow exceptions.

The court also explored the broader implications of changing that rule.

Justice Samuel Alito raised questions about how limits on birthright citizenship would affect families, particularly those with long-term ties to the country.

Sauer argued that countries with stricter citizenship rules do not face a â??huge humanitarian crisis,â?? suggesting the US could move in a similar direction.

He also pointed to changes in the global environment, noting that â??eight billion people are one plane ride awayâ?? from the United States.

Opponents warned that such reasoning risks overturning settled law.

They pointed to the Supreme Courtâ??s 1898 ruling in United States v. Wong Kim Ark, which affirmed that most children born in the US are citizens regardless of their parentsâ?? status.

The 14th Amendment, ratified in 1868, overturned the Dred Scott decision and established a national definition of citizenship.

For more than a century, the US has followed a broad birthright citizenship rule.

The courtâ??s decision could determine whether that approach continues -- or shifts closer to practices seen in other parts of the world.

/IANS