You either have a homeland or you don't have one, he recently said. And he is far from being the only US politician who supports that position. Most Republican candidates either share the same opinion or they are still hesitating about it. But none are outright rejecting it. Only Jeb Bush, whose wife was born in Mexico, and Marco Rubio, who is the son of Cuban immigrants, have publicly stated that they support the current system of obtaining citizenship.
Article 1 of the 14th Amendment says that all persons born or naturalised in the US and being into US jurisdiction are US citizens and citizens of the state in which they live. And no state could adopt laws that restrict the privileges and liberties of the citizens of the United States.
This amendment is from 1868, and it stipulates how US citizenship could be granted to immigrants. But now the debate is which US-born children are under US jurisdiction and which aren't. Almost all participants in this debate hold the position that the children of foreign diplomats who are born in the US should not be considered US citizens by birth. But it gets more complicated when we are talking about US-born children of illegal immigrants, or foreign students, or tourists, etc.
Indeed, tens of thousands of pregnant women arrive in the US with the purpose of giving birth on US territory. For example, 30 thousand come from Asia on a so called "birth tourism". Most of them arrive in California. In the months before giving birth, they settle mostly in South California, where in time their kids would be granted the right to visit free public schools and universities. And while many are seeing a drain on the economy in this, the Constitution is very clear on the question who automatically gets US citizenship.
The 1868 amendment was adopted after the Civil War. The idea was to put an end to racial discrimination by including not only the freed African American slaves into the system of US citizenship, but also all persons who are born or naturalised in the US or who are under US jurisdiction. It is very clear that the authors of this amendment intended to include everybody.
When we look around the world, in fact it turns out such a practice exists in very few places. Only 30 countries, most of them in North and South America, grant automatic citizenship to people who are born on their territory. And the US and Canada are the only ones among the developed countries in that regard.
Most countries consider nationality as something that is transferred from generation to generation - by bloodline, so to speak. But things are different in America: it is a country that has gathered people from all around the world from its very inception, and this diversity is built into the fabric of the American society.
So if the rule for granting US citizenship by birth is abolished, this would fundamentally change the understanding, the purpose, and the character of the American nation. The most important implication of this amendment is that it has been a very successful tool for integration. If it weren't there, there would be a whole generation, or maybe even several generations that would have never been assimilated, because they would have lacked equal rights with the rest of society. And America would have had ethnic problems that are similar to the ones Europe is having right now. So before indulging in populism, perhaps the politicians and their media friends should think very carefully what they are actually advocating for.