Agree. But it was Ike who originated the metaphor of the domino, in a speech, not LBJ. The idea was passed from Ike to JFK to LBJ, and really got its start with Truman and his doctrine.
If we continue on this trade war path, we will have to subsidize farmers to leave land fallow, as has been done in the past, or persuade nations like Brazil that it's better to buy soybeans from us than clear rainforest to grow their own. That would mean pricing that would continue to kill off small farms and drive overproduction. Really, the best path is to end overproduction, reduce cropland, and just produce food for the domestic market. This would help conserve good soil and clean water for future generations. And would give many farmers a stable source of income from their land, regardless of drought/flood cycles.