An excellent analogy from Joy Pullmann writing at the Federalist:
The Border Hoppers Liberals Don’t Love
School districts jail and sue parents for trying to get their kids into better schools in places they can’t afford to live. . . .
And, as with open enrollment, if the United States reduces social welfare programs so new arrivals are less likely to further subdivide existing resources or to take when they haven’t contributed, current citizens will naturally be more welcoming. When something is a zero-sum game, things get ugly. Optimal is a system where everyone wins. And that’s possible.
Another central question is whether America ought to prioritize the citizens we already have. That would include schoolchildren trapped in terrible public schools, whose flight to better schools is often stymied or pooh-poohed by the very same people who welcome non-citizens with open arms.
The analogy could be expanded.