The nation's highest court agrees to hear legal challenge disputing automatic citizenship for those born in the US.

The top court has will hear a pivotal case that puts to the test a century-old guarantee: automatic citizenship for people born within US borders.

On the inaugural day in office this January, President Donald Trump issued an executive order aiming to terminate this practice, but the move was subsequently blocked by lower courts after constitutional questions were brought forward.

The Supreme Court's ultimate decision will either support citizenship rights for the infants of foreign nationals who are in the US undocumented or on temporary visas, or it will overturn the provision entirely.

Next, the justices will calendar a session to hear the case between the administration and claimants, which comprise parents who are immigrants and their young children.

The Legal Foundation

For nearly 160 years, the Fourteenth Amendment has codified the rule that anyone born in the country is a American citizen, with exceptions for children born to embassy personnel and personnel of invading forces.

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

The challenged directive sought to refuse citizenship to the children of people who are whether in the US without legal status or are in the country on temporary visas.

The United States belongs to a group of about 30 countries – mostly in the Western Hemisphere – that award instant citizenship to any person born in their territory.