As things are, any child born in the United States is entitled to US citizenship. But this begs the very important question of whether their parents are themselves here legally. Quite frankly, there is nothing immoral, not one little bit, about denying citizenship privileges to the offspring of illegals. Their children are not entitled to it simply and perhaps solely for the reason that they should not have been here to be born in first place.
Such birthright privileges are not fundamental rights. The United States, just like any other nation, has both the right to set reasonable citizenship qualifications as well as to alter its basic law, so long as a true moral evil is not involved. This is nowhere near a moral wrong.
Democrats don't like this idea, as the presumption is that many illegals support them. All right, illegals and their children may lean Democrat. If so, then such becomes another important issue: those not here legally have no right to influence our political system regardless of their personal philosophical leaning. Such things are, at the least, improper and at the most, downright immoral. No non-American citizen has the right to influence the direction of our country. To our libertarian friends we ask: is this really any different than the US attempting to interfere with the internal workings of other countries?
This is not xenophobic. Anyone who wants to become an American citizen who is no threat to our nation ought to be allowed to become citizens: relatively open borders are not a bad thing. But come in through the front door. Because coming in through the back is itself suspect behavior, and grounds alone for denying anyone the rights of legal citizenship.