Trump has no intention of stopping birthright citizenship
If Donald Trump tries to stop birthright citizenship using an executive order, it will be blocked by the courts for years and then, probably after he's out of office, quietly dismissed. Congress would probably get involved somewhere along the line (link). As in other cases, the [[establishment media]] would endlessly demagogue the issue, turning many against Trump's plan.
What Trump is doing is all just a scam to increase turnout in the upcoming elections.
If Trump were sincere about reducing the use of birthright citizenship, all he has to do is make smart arguments that turn some in the Democratic Party base against their leaders. Dem leaders strongly enable illegal immigration and that makes them extremely vulnerable. Trump could undercut them by pointing out to their base that their leaders are helping Big Business lower wages. If Trump did that in smart ways, he'd reduce illegal immigration and thus reduce the numbers of children born in the U.S. to illegal alien parents.
Do you see Trump doing that? Of course not: this is just a stunt. This is just like the stunts George W Bush pulled, like riding around the border in a Border Patrol dune buggy. Like Trump, the last thing he was going to do was try to undercut his colleagues in the Dem leadership or his friends in Big Business.
That doesn't mean Trump's cheap, deceptive stunt might not help the GOP.
Trump's fans will be tricked yet again into thinking Trump has their back on immigration. Conservative pathologies will come into play: they think they're a majority when they aren't, they're ignorant of how things work, they're lazy, and they can't tell the difference between what you want and how you get it. Strong arguments against birthright citizenship would be required as a necessary first step. Trump can't even conceive of those strong arguments and his fans won't demand he uses them. Trump fans will think the only way to stop birthright citizenship is how Trump proposes it. Trump will yet against troll the left and they'll do their part to help him as they always do. Those with access to Trump or his proxies won't press him on how unfeasible his proposal is, but will instead just play right into his hands. Trump fans will confuse those who oppose how Trump does things with those who oppose what he pretends to want, alienating potential allies.
As a result of all that, Trump might increase GOP turnout. But, at the same time, he might also rile up part of the Dem base.
Want to do something about Trump's latest attempt to fool millions of people? Urge those with access to Trump proxies to really press them on why Trump doesn't go after Big Business and other pull factors.