America's top judicial body has decided to review lawsuit questioning citizenship by birth.

The US Supreme Court has decided to review a landmark case that questions a historic constitutional right: guaranteed citizenship for people born in the United States.

On day one in office this winter, President Donald Trump enacted a directive aiming to end this practice, but the move was halted by lower courts after lawsuits were brought forward.

The Supreme Court's final ruling will ultimately support citizenship rights for the infants of foreign nationals who are in the US illegally or on temporary visas, or it will end them completely.

Next, the court will calendar a session to hear oral arguments between the administration and the suing parties, which include immigrant parents and their young children.

A Constitutional Cornerstone

For nearly 160 years, the 14th Amendment has codified the rule that every person born in the United States is a American citizen, with exceptions for children born to embassy personnel and members of foreign military forces.

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

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

The United States is one of about three dozen nations – mostly in the Americas – that award instant citizenship to all those born in their territory.