[vizeroth]

So why did the U.S. sign the Mexican Farm Labor Agreement in 1942? The Migrant Labor Agreement of 1951? Why did the UFW hold protests at the U.S. border in 1969-1973? Why did the Immigration Reform and Control Act of 1986 specifically address agricultural workers?

Importing large numbers of foreign workers, migrant or otherwise, has been the backbone of the agricultural labor market in the U.S. since the country was founded. It's not necessarily a good thing, just not a recent thing by any means.

[Spooky23]

Mexican agricultural workers have always been a thing. But the concentration of farm output to a few regions of California is a recent phenomenon, and the resulting industrialization of agriculture was a thing.

When I was a teen in the early 90s, I worked on a 500 acre farm in upstate ny. At that time it was possible to support a family and a few workers on land like that with a diversified crop of dairy, hay, something like oats and a few other things. The neighboring farm grew vegetables.

That is no longer possible. 90% of farms within 75 miles <250 acres are hobby farms, growing subsidized corn, or are legacy dairy farms that will be subdivisions when the farmer is too old to work or his equipment wears out.