Once again, what was once a crazy idea talked about on the far right has become the stated policy of Republican Senators. Not that the GOP is truly serious about taking away birthright citizenship. Amending the Constitution is really, really hard, not to mention that opening this can of worms might even come back and bite white people in the ass.
Think about it.
I know conservative think that birthright citizenship is solely the domain of brown people come fresh to America. But most white people came to the States in earlier eras, where the paperwork of immigration was much less or non-existent. So you have to show your parents papers to prove you're a citizen? Where is your Mom's papers? Your Grandma's? Your Great-Great-Great who came over back when. If only citizens can give birth to citizens, then you have to prove your ancestor were here legally. Could you do that? Remember, in the new tea party regime, having a birth certificate is not enough.
That's just one complication. How about mixed marriages? What if mom is a citizen and Dad's student visa has expired? Is the kid legal? There's a reason why we have birthright citizenship - in a nation of immigrants and ever-changing immigration laws, it keeps things simple. Born here, citizen.