The nation's highest court agrees to hear case questioning citizenship by birth.

The US Supreme Court has agreed to take on a pivotal case that puts to the test a century-old constitutional right: automatic citizenship for those born within US borders.

On his first day in office this January, the President signed an order aiming to end the policy, but the move was halted by federal courts after lawsuits were initiated.

The Supreme Court's eventual decision will either uphold citizenship rights for the offspring of foreign nationals who are in the US illegally or on temporary visas, or it will end the provision altogether.

Next, the court will calendar a session to hear oral arguments between the government and the suing parties, which include foreign-born parents and their infants.

The 14th Amendment

For over a century and a half, the Fourteenth Amendment has enshrined the principle that anyone born in the nation is a citizen, with exceptions for children born to embassy personnel and members of occupying armies.

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

The challenged presidential order sought to refuse citizenship to the offspring of people who are either in the US illegally or are in the country on temporary visas.

The United States belongs to a group of about three dozen nations – largely in the North and South America – that award immediate citizenship to any person born on their soil.