The Supreme Court has affirmed the unlawfulness of Executive Order 14160, which sought to deny citizenship to children born in the United States to parents unlawfully or only temporarily present in the country. The order had argued that such children are not "subject to the jurisdiction" of the United States within the meaning of the Fourteenth Amendment's Citizenship Clause.
The Court held that the Citizenship Clause codified the common-law rule of jus soli, under which any child born on American soil and not exempted by the narrow historical exceptions for children of foreign diplomats or members of sovereign Indian tribes is a citizen at birth, regardless of the parents' domicile or immigration status. Tracing the Clause's history from English common law through its adoption as a repudiation of Dred Scott, and relying on the Court's 1898 decision in United States v. Wong Kim Ark, the majority rejected the government's argument that only noncitizens domiciled in the United States could transmit "sufficient allegiance" to their children.
The full text of Trump v. Barbara can be found here: https://www.supremecourt.gov/opinions/25pdf/25-365_diff_ed9g.pdf