I live on the outskirts of a "sanctuary city" (Austin, TX). So far I have not noticed any personal impact from its adoption of that practice.
Now comes Trump, who will cut off their federal funding. You can read about it here:
And it also appears that Governor Greg Abbott is going after sheriffs who don't cooperate with immigration officials. You can read about it here:
The "sanctuary" movement seems to have similarities with the anti-slavery movement prior to the US Civil War and its "underground railroad". Chief among these are the reasons people were seeking sanctuary in the first place (i.e., the impact of NAFTA on Mexico is the modern equivalent of slavery).
So if we are the cause, doesn't it make sense that we also should be the cure?
With that in mind, consider the outcome of the anti-slavery movement - slavery was officially abolished, but its affects are still with us today. Why? Because we never addressed them, not then and not now.
I suspect the same thing is going to happen again. We'll muddle through and "fix" the current crisis, but we will not address the root causes of the problem - (1) globalism, (2) "free trade" policies, and (3) our rapacious lifestyle. Trump is attacking (1) and (2), but only We The People can address (3). And I don't think we will, not unless we're forced to.
This is a global problem with common causes everywhere. A return to nationalism, which I personally favor, is not likely to succeed. There are too many powerful forces against it, and it ultimately condemns billions of people to starvation.
So what now?