I think if there's a rational reasoning behind Trump unleashing ICE and the national guard on the domestic population, this must be it: "the economy is doing really bad, and we need a smokescreen so people won't talk about it."
Hmmm kinda ties into the whole problem of well-off/happy people not being particularly eager to chant "foreigners out", but when they're desperate they take any explanation for their misery they can get their hands on that sounds workable (because, no, you can't go up to a billionaire and just "take all their stuff", but you CAN beat up a foreigner or other disadvantaged person that is worse off than you)
I think another reason for the recent global rise of anti-immigration parties is also that the relative economic value of immigrants (as unskilled labor) has gone down, and the "costs" (cultural/language friction) have become more visible.
Declining number of workers in farming are also a factor, but I'm thinking more construction/heavy industry.
It used to be extremely economical to import workers and use them to grow local industry: It does not only save you the cost of educating them, but also the productivity loss on the parents side. It was a huge economical boost, and pretty much a win-win situation all around (exact same thing happened in other countries, like Germany).
But the situation changed, and the same influx of workers to build and staff fields and factories is no longer as helpful; the main current/future need has shifted towards nursing/caretaking, and in that sector its much more about meeting demand cost effectively than fueling growth: The median age citizen does not benefit from more/cheaper nurses to the same degree than they did from a growing economy/industry half a century ago.
