The U.S. Supreme Court rejected a central plank of U.S. President Donald Trump¡¯s immigration agenda on Tuesday, deeming his plan to restrict birthright citizenship to be unconstitutional.

The divided court said an executive order Trump issued hours after his inauguration last year couldn¡¯t be squared with the U.S. Constitution¡¯s 14th Amendment, which has long been understood as guaranteeing citizenship to virtually everyone born on U.S. soil.

The case tested what it means to be an American. Trump¡¯s order sought to restrict birthright citizenship to babies with at least one parent who is a U.S. citizen or green-card holder, affecting an estimated 250,000 children born to undocumented immigrants and temporary visitors each year.