America's top judicial body agrees to review case questioning citizenship by birth.

The nation's highest court has decided to review a landmark case that challenges a century-old principle: guaranteed citizenship for individuals born within US borders.

On the inaugural day in office this January, President Donald Trump issued an executive order aiming to halt birthright citizenship, but the order was subsequently blocked by the judiciary after lawsuits were brought forward.

The Supreme Court's final ruling will either affirm citizenship rights for the children of foreign nationals who are in the US illegally or on temporary visas, or it will overturn the provision altogether.

Next, the court will set a time to hear oral arguments between the administration and plaintiffs, which involve foreign-born parents and their newborns.

A Constitutional Cornerstone

For over a century and a half, the Fourteenth Amendment has enshrined the rule that all individuals born in the United States is a American citizen, with certain exclusions for children born to diplomats and members of occupying armies.

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

The disputed executive order sought to withhold citizenship to the offspring of people who are either in the US illegally or are in the country on short-term status.

The United States is among about a minority of states – largely in the North and South America – that award instant citizenship to any person born in their territory.