This granting of citizenship to children born in the US - regardless of what nationality their parents are - is in the first section of the 14th amendment to the Constitution. That section also bans the denial of rights without due process and forbids states from giving anyone unequal protection of the laws. Good luck at overturning that.
Wil Wilkinson tries defending this in the normally intelligent The Week.
But here's my question: suppose everyone had to earn citizenship the same way immigrants do? You couldn't register for the army, vote, or do any of your civic duties unless you pass the same tests that immigrants do? How would Americans measure up to the standards they place on those wanting to become Americans?
In a 2006 survey held by the McCormick Tribune Freedom Museum, 23% of respondents knew freedom of religion was one of the freedoms guaranteed by the first amendment. 21% thought the right to own a pet was one of them, and 17% thought the right to drive a car was one. Only one tenth of one percent was able to name all five (speech, press, religion, assembly, petition for redress of grievances).
2/3rds of respondents in a later poll couldn't name a single branch of government.
And so on. How many Americans know what we purchased from France in 1803 or what Susan B. Anthony did or name one Indian tribe?
To be fair, the people who take the test have studied, and presumably everyone else would have to study hard too if it meant being a full citizen. But wouldn't it be nice if everyone actually KNEW civics and weren't fooled by radio blabbermouths who think that a clause in the constitution about slavery was actually about immigration?