That is ABSOLUTELY right, and the logic came from an Amicus Curiae brief by Ed Meese and John Eastman in the Hamdi case.
Means Vitter is getting GOOD advice on the issue, because that is the thing to zero in on.
There should be a massive groundswell to support him.
I agree. The pertinents clause in the 14A specifies: "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."
Note that first use of "and" - that is what Vitter is pointing out. The 14A clearly states that being here isn't enough - you also ("and") have to be" subject to the jurisdiction thereof." But BY DEFINITION, someone here ILLEGALLY is NOT "subject to the jurisdiction" of the United States, in the sense that their illegal status means that they have rejected the jurisidiction (acceptance of the laws) of the US by the WAY they arrived - illegally.
Go, Vitter, go!