In the House, a group of immigration hard-liners thinks this precept that has been around for a century and a half is a detriment to the nation because, they say, it can serve as a magnet for undocumented people to slip across the border and bear children. Such offspring can eventually serve as the “anchor” that other family members may use to gain citizenship themselves.
According to this point of view, many pregnant women, or young couples of childbearing age, may decide to try to get to U.S. soil so the children will reap American citizenship and the opportunities and benefits that go with it.
And once the children reach age 21, they can begin to sponsor family members to legally immigrate. To Rep. Tom Tancredo, R-Colo., and others on a House immigration task force, that effectively rewards those who break immigration laws.
Citizenship “should not be bestowed on people who are the children of folks who come into this country illegally,” Tancredo said.
But critics of doing away with what is sometimes called “birthright citizenship” say the constitutional provision has actually been a boon for the United States, one of the few countries in the world to grant such immediate status.
By embracing all babies at birth as Americans, the nation has avoided the societal unrest that has festered in France, where even the French-born children of Arab and other legal immigrants do not automatically become citizens until they reach 18.
Resentment and discrimination from that segregated status is blamed for contributing to the rage that exploded into riots in recent weeks across France.
“It has served us well by giving (everyone born in the United States) the sense of belonging from day one,” said Demetrios Papademetriou, president of the Migration Policy Institute in Washington. “It’s how we built our country.” ~Scripps-Howard News Service 
Where does Mr. Papademetriou go astray? He assumes that citizenship in this country implies a sense of belonging. That is exactly what birthright citizenship does not do–it provides membership in the polity on the basis of nothing more than an accident of birth. That it was originally designed to counteract that other accident of birth, namely servile status, is no excuse. The proper solution is to make a requirement that newborn children are citizens only if at least one parent is already a citizen, whether native or naturalised. That would require some greater conscious commitment on the part of the parents to adapt to this country, and it would prevent the abuse of the 14th Amendment provision that is obviously egregious and indefensible.
Belonging implies meaning, and for citizenship to be meaningful it must have been actively embraced and then inculcated in one’s children. We (and this includes many of the fans of mass immigration) don’t assume that people who come to this country should be spared the process of naturalisation, nor do we assume that native-born children automatically understand their roles as citizens but instead have to be educated in these things by their parents and (God help us) their teachers. Ending birthright citizenship would force immigrants to become at least a little better acquainted with this country by making sure that every new citizen has had to be raised up by citizen parents, so that their children’s integration, such as it is, is premised on their own willingness to become fully American.
Incidentally, the French integration model allows for naturalisation, and, as so many dimwits have been fond of pointing out in the last month, many of the rioting “youths” were technically French citizens–so much for the sense of belonging! Citizenship is a legal and political category–it does not carry much meaning for those not raised in the cultural traditions of the peoples who fashioned the Republic and transmitted the constitutional and legal principles embodied in our institutions and laws. Citizenship is, as Steve Sailer  correctly pointed out in another context, an extremely weak and relatively unnatural form of allegiance. It may excite fewer passions, but it also stirs relatively little loyalty unless it is augmented by other more natural affinities that give that citizenship some heft and substance.
I might put it, perhaps a bit too simplistically, this way: I am not a patriot because I am a good citizen, but I am a good citizen because I am a patriot. And so on. As important as the land may be to patriotism, simply being born on its soil does not in itself lay the foundations for patriotic instinct. This instinct grows through living a particular way of life suited to that land, and through accommodating oneself to that way of life.
Ending birthright citizenship will also clarify a bit more whose birthright this country is and whose it is not.