US Supreme Court will review case questioning birthright citizenship.

The nation's highest court has will hear a pivotal case that puts to the test a longstanding constitutional right: guaranteed citizenship for those born on American soil.

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

The Supreme Court's eventual ruling will ultimately affirm citizenship rights for the infants of foreign nationals who are in the US illegally or on short-term permits, or it will end the provision completely.

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

A Constitutional Cornerstone

For nearly 160 years, the 14th Amendment has enshrined the rule that all individuals born in the United States is a American citizen, with specific conditions for children born to foreign diplomats and members of invading forces.

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

The contested presidential order sought to withhold citizenship to the offspring of people who are whether in the US in violation of immigration law or are in the country on temporary visas.

The United States belongs to a group of about three dozen nations – mostly in the Western Hemisphere – that grant automatic citizenship to anyone born within their borders.