America's top judicial body agrees to hear legal challenge disputing automatic citizenship for those born in the US.

The top court has decided to review a pivotal case that puts to the test a longstanding guarantee: birthright citizenship for individuals born in the United States.

On day one in office this January, President Donald Trump signed an order aiming to terminate the policy, but the order was halted by the judiciary after legal challenges were filed.

The Supreme Court's final decision will ultimately affirm citizenship rights for the children of immigrants who are in the US undocumented or on short-term permits, or it will end the provision completely.

Next, the judges will set a time to hear arguments between the administration and plaintiffs, which include immigrant parents and their infants.

A Constitutional Cornerstone

For nearly 160 years, the Fourteenth Amendment has established the principle that every person born in the United States is a US citizen, with certain exclusions for children born to diplomats and members of foreign military forces.

"Every individual born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States."

The contested executive order sought to deny citizenship to the children of people who are whether in the US in violation of immigration law or are in the country on non-permanent visas.

The United States is among about 30 countries – largely in the Western Hemisphere – that grant instant citizenship to anyone born in their territory.