The US Supreme Court is poised to deliver its much anticipated and debated decision on the question of birthright citizenship.

At the centre of the case (known as Trump v. Barbara) is an executive order signed by President Donald Trump on his first day of office in 2025, barring citizenship for children born to parents illegally in the United States or on long-term visas.

Americans have long held that the 14th Amendment to the Constitution grants automatic citizenship for babies born on US soil. Trump disagrees.

The case is also one more example of how citizenship and residency in many countries – including New Zealand – has become an increasingly vexatious issue in an age of massive migration.

Constitutional challenge

The 14th Amendment, passed after the American Civil War, 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.

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.

A decisive case in 1898 largely established that babies born in the US are legally citizens. But the Trump administration argued the 14th Amendment only applied to former slaves.

That would mean babies born to individuals who are not “domiciled” – thus not owing allegiance to the US – are not citizens under the amendment.

Solicitor General D. John Sauer argued the........

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