The nation's highest court agrees to review legal challenge disputing citizenship by birth.

The top court has agreed to take on a significant case that puts to the test a longstanding guarantee: guaranteed citizenship for people born in the United States.

On day one in office this winter, the President enacted a directive aiming to halt the policy, but the action was subsequently blocked by federal courts after constitutional questions were brought forward.

The Supreme Court's final judgment will ultimately uphold citizenship rights for the infants of foreign nationals who are in the US without authorization or on temporary visas, or it will overturn the provision altogether.

Next, the judges will set a time to hear oral arguments between the federal government and claimants, which comprise parents who are immigrants and their young children.

The 14th Amendment

For nearly 160 years, the Fourteenth Amendment has enshrined the doctrine that every person born in the country is a American citizen, with certain exclusions for children born to diplomats and personnel of foreign military forces.

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

The disputed presidential order sought to refuse citizenship to the offspring of people who are either in the US without legal status or are in the country on non-permanent visas.

The United States is among about three dozen nations – largely in the Americas – that grant immediate citizenship to anyone born on their soil.