A while back foodies attacked NAFTA for permitting US farmers to export cheap corn into Mexico, thereby undermining small farmers in Mexico.
There's controversy over the constitutionality of "research and promotion orders", the Hass Avocado Board operates as the result of one.
Now the avocado is surging in popularity as described here. One might assume that the importing of avocados from Mexico has ruined the market for California growers. But looking closely at the charts there, that doesn't seem to be the case. Imports have grown tremendously, but US production has also grown, if not so fast (it appears US avocados went from 600 million in 2007 to 1 billion in 2013.) It seems at least for the moment that the combination of free trade (NAFTA) and government interference (the Avocado Board) have produced prosperity for everyone, at least as long as California doesn't dry up.