On birthright citizenship, Trump said he would seek to repeal it via executive action — which would be certain to spark immediate legal challenges.
“We have to end it,” Trump said, calling it “ridiculous.”
Trump suggested that birthright citizenship is uniquely American, saying, “We’re the only country that has it, you know.” But according to a review by the Library of Congress, more than 30 nations provide birthright citizenship, including Canada and Brazil.
The Citizenship Clause of the Fourteenth Amendment says: "All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside."
Trump and his supporters (including some writers for National Review) may draw support from the phrase “and subject to the jurisdiction thereof.” Some have argued that this language must exclude the children of aliens from citizenship, because aliens owe allegiance to another nation and hence are not under “the jurisdiction” of the United States. But the constitutional text requires only that the children born in the United States fall subject to American jurisdiction, which means that they are governed by American law. Almost all aliens in the United States, even citizens of other nations, still fall within our jurisdiction while they are in our territory: Otherwise they could commit crimes of all sorts without fear of punishment. Other uses of “jurisdiction” in the Constitution, such as in the 13th and 14th Amendments, also refer to the power to govern by law, not national allegiance.
Instead, “subject to the jurisdiction thereof” refers to certain discrete categories of people excluded from citizenship, even though they might be born on U.S. territory. These include the children of diplomats and enemy soldiers at war who are occupying territory. These individuals could be on U.S. territory, but are not subject to U.S. law. A third and obvious category was American Indians. At the time of the 14th Amendment, American Indians were still considered semi-sovereigns who governed themselves with their own laws and made treaties with the United States. But “subject to the jurisdiction thereof” did not grant Congress the power to pick and choose among different ethnic and national groups for citizenship. Instead, the phrase recognized a few narrow exceptions to the general principle of birthright citizenship that has prevailed throughout American history.