The nation's highest court will hear lawsuit challenging automatic citizenship for those born in the US.

The top court has will hear a landmark case that challenges a longstanding guarantee: birthright citizenship for individuals born within US borders.

On his first day in office this January, President Donald Trump issued an executive order aiming to end birthright citizenship, but the action was halted by lower courts after legal challenges were brought forward.

The Supreme Court's final ruling will ultimately support citizenship rights for the children of foreign nationals who are in the US illegally or on non-immigrant visas, or it will overturn them entirely.

Next, the judges will set a time to hear the case between the government and the suing parties, which involve parents who are immigrants and their young children.

The 14th Amendment

For over a century and a half, the Fourteenth Amendment has codified the rule that every person born in the country is a US citizen, with certain exclusions 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 contested directive sought to refuse citizenship to the children of people who are either 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 – largely in the North and South America – that award instant citizenship to any person born on their soil.