"It is my study of the matter," professor Douglas Kmiec of Pepperdine University School of Law told ABC News, "that those who wrote the 14th Amendment intended those words ["the jurisdiction thereof"] to mean not owing allegiance to anybody else -- that is, subject to the complete jurisdiction of the United States, not simply to the laws of the United States or subject to the jurisdiction of the court."
Kmiec, who served former Presidents Ronald Regan and George H.W. Bush as constitutional legal counsel, said that someone who enters the U.S. illegally, and has not renounced the citizenship of the country from which he or she has emigrated, is not subject to the complete jurisdiction of the United States.
Gingrey shares Kmiec's assessment that Congress likely has the power to end birthright citizenship through legislation. But he would like to see Congress take that step regardless of whether it required a constitutional amendment or not, and he is encouraged by Romney's recent comments.
I would be "pleased to know that he would stand strong against that and eliminate birthright citizenship," said Gingrey.
When it comes to dealing with the roughly 12 million illegal immigrants currently in the United States, Romney's rhetoric has departed not only from McCain but also from that of President Bush and his circle of advisers.
In a March 26 memo to members of the Republican National Committee, former Bush strategist Matthew Dodd maintained that voters "don't consider granting legal status to those already here [on] amnesty." Dowd urged R.N.C. members to pursue a "comprehensive" solution to immigration with an eye on the country's burgeoning Hispanic population. But Romney has still used the "amnesty" label to tar his chief rival for the GOP's 2008 presidential nomination.
Speaking of McCain, Romney recently told "Nightline," "his immigration bill, I think, is an amnesty-style program that I don't support."
McCain rejects the "amnesty" label.
"Amnesty is forgiveness," McCain told ABC News' "Good Morning America" in the spring of 2006. "This is payment of a fine. This is admission of guilt. . . This is earned citizenship, that's what it is."
But by branding McCain's proposal to offer them a path to citizenship as "amnesty," as he regularly does, Romney has struck a chord with some of his backers in the House.
"He is strong on border security, and he is against amnesty," Gingrey told ABC News, "and that is certainly part of the reason why I am so enthusiastic in my support for Gov. Romney."