US Supreme Court will hear case questioning birthright citizenship.

The US Supreme Court has will hear a landmark case that challenges a century-old principle: birthright 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 move was subsequently blocked by lower courts after lawsuits were filed.

The Supreme Court's final decision will ultimately uphold citizenship rights for the children of immigrants who are in the US without authorization or on non-immigrant visas, or it will nullify those rights entirely.

Next, the justices will calendar a session to hear the case between the federal government and claimants, which comprise foreign-born parents and their newborns.

The 14th Amendment

For more than 150 years, the Fourteenth Amendment has enshrined the rule that anyone born in the United States is a US citizen, with exceptions for children born to diplomats and personnel 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 directive sought to withhold citizenship to the children of people who are whether in the US without legal status or are in the country on short-term status.

The United States belongs to a group of about 30 countries – largely in the Americas – that award instant citizenship to all those born on their soil.