In the Oval Office on Thursday, Donald Trump signed another executive order aimed at narrowing birthright citizenship, a right that the United States Supreme Court reaffirmed as recently as late June. The new order takes particular aim at foreign nationals who, in the administration's view, travel to the United States under the pretence of tourism while intending to give birth on American soil — a practice Trump described as having made "a joke" of the constitutional guarantee. It also targets, according to senior adviser Stephen Miller, children of members of foreign terrorist organisations and broad categories of individuals who act on behalf of foreign governments. The legal obstacle the administration faces is substantial.

The Fourteenth Amendment, ratified in 1868 in the aftermath of the Civil War, states that all persons born or naturalised in the United States and subject to its jurisdiction are citizens. Earlier this year, a majority of the Supreme Court, led by Chief Justice John Roberts and joined by both conservative and liberal justices, struck down Trump's first executive order on the same grounds. Lower courts had reached the same conclusion, ruling that almost everyone born on American soil is constitutionally entitled to citizenship, with narrow exceptions such as the children of foreign diplomats. The administration has long argued that the Fourteenth Amendment was designed solely to secure the rights of formerly enslaved people and does not extend to children of undocumented migrants or temporary visa holders.

Critics, including constitutional scholars, reject that reading as historically selective and legally unsound.