The senators who debated the amendment.
"Senator Edgar Cowan (R-PA) – who would later vote against the entire constitutional amendment anyway – was the first to speak in opposition to extending birthright citizenship to the children of foreigners. Cowan declared that, “if [a state] were overrun by another and a different race, it would have the right to absolutely expel them.” He feared that the Howard amendment would effectively deprive states of the authority to expel persons of different races – in particular, the Gypsies in his home state of Pennsylvania and the Chinese in California – by granting their children citizenship and thereby enabling foreign populations to overrun the country. Cowan objected especially to granting birthright citizenship to the children of aliens who “owe [the U.S.] no allegiance [and] who pretend to owe none,” and to those who regularly commit “trespass” within the U.S.
[22]
In response, proponents of the Howard amendment
endorsed Cowan’s interpretation. Senator John Conness (R-CA) responded specifically to Cowan’s concerns about extending birthright citizenship to the children of Chinese immigrants:
Conness acknowledged Cowan’s dire predictions of foreign overpopulation, but explained that, although legally correct, Cowan’s parade of horribles would not be realized, because most Chinese would not take advantage of such rights although entitled to them. He noted that most Chinese work and then return to their home countries, rather than start families in the U.S. Conness thus concluded that, if Cowan “knew as much of the Chinese and their habits as he professes to do of the Gypsies, … he would not be alarmed.”
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No Senator took issue with the consensus interpretation adopted by Howard, Cowan, and Conness. To be sure, one interpretive dispute did arise. Senators disagreed over whether the Howard amendment would extend birthright citizenship to the children of Indians. For although Indian tribes resided within U.S. territory, weren’t they also sovereign entities not subject to the jurisdiction of Congress?"
The Citizenship Clause applies to the children of aliens and citizens alike. But that may not stop Congress from repealing birthright citizenship.
thefederalist.com