"The side that stays within its fortifications is beaten." ~Napoleon
"It's always reassuring to find you've made the right enemies." -- William J. Donovan
Illegal immigrant labor, I have no argument with you. Legal immigrant labor is a function of policy, and maybe that policy is crap in some regards, but this balance you speak of is on a knife's edge. It is easy to embrace one element of protectionism, then world reacts to it in a way you don't want them to, and then the protectionist country's only recourse is more protectionism and trade war, and then you have a positive feedback loop. We could go down that path and be self-sufficient cut off from the rest of the world, but our living standards would plummet relative to what we enjoy now.There is a balance. A balance at which we, as a nation can produce the goods and services we need without under the table immigrant labor or labor of nations that pay near nothing.
"The knowledge and prudence of the poor themselves, are absolutely the only means by which any general and permanent improvement in their condition can be effected." - Thomas Malthus
The answer is - the degree of globalization has changed. Every POTUS in my lifetime has pushed for increased globalization, almost always in direct opposition to the will of the people.