Racism and xenaphobia of the native population has very little effect on migration if the reward for the migrants is enough.
If a "developed" country wanted to stop migration they would work to raise the living standards at the source. There is less chance of that happening than removing xenaphobic behaviour from the natives however.
Or the "developed" society becomes more brutal than the place the migrant are fleeing from, so they stay away out of fear.
If you look at Haiti, Venezuela, etc, it seems the limiting factor here is an unwillingness of the U.S. to leverage any political muscle, either domestically or internationally. I presume that's partly a consequence of Iraq and Afghanistan, but also probably because for some large factions, especially on the left but increasingly on the right, in American politics any form of involvement is unacceptable. It's almost like a radical ecological argument: the rest of the world is in a state of nature, and any intervention by an external agency is per se morally evil; the moral imperative is non-intervention, outcomes are irrelevant. Even those who don't hold this belief (explicitly or implicitly) at least understand the consequences: any perceived failure in intervention will be blamed on them, and nobody wants to face the ire of the religionists.
> It's almost like a leftist ecological argument: the rest of the world is in a state of nature, and any intervention by an external agency is per se morally evil.
The USA will get flack if it meddles and if it doesn't meddle, they really shouldn't worry about world opinion at that point. More to the point, it is impossible for America to fix the rest of the world, even if that were the moral thing to do. Welcoming some immigrants from countries having problems is probably the best we can do.
There's a huge gap between isolationism and trying to "fix the rest of the world". But in the current political epoch nuance, pragmatism, and mercy seem to be alien concepts.
The USA already has a foreign aid budget, and gets involved in bits and pieces, but it’s always too much and not enough at the same time, so how can they win at that?
If a "developed" country wanted to stop migration they would work to raise the living standards at the source. There is less chance of that happening than removing xenaphobic behaviour from the natives however.
Or the "developed" society becomes more brutal than the place the migrant are fleeing from, so they stay away out of fear.