What did Donald Trump do today?

He told farmers they were planting the wrong crops.

Trump tried to spin his on-again, off-again tariffs on the United States' largest trading partners this way in a post to his boutique social media platform:

There's no real mystery as to what will happen if retaliatory tariffs deprive American farmers of the natural market for their products, because it happened already in Trump's first term. Crop prices will drop, which will cause farms to fail. Businesses that rely on farms will fail too, costing hundreds of thousands of jobs. Massive bailouts will be required to prop up the entire agriculture sector. There was even a rash of suicides as a result of farm bankruptcies the last time Trump tried this.

Trump's post implies that farmers can simply sell the same products to domestic customers. This is, to put it gently, absurd. American farmers already sell their products in the United States, but almost $200 billion worth of products are grown with the export market in mind. Trying to flood the domestic market with these crops on short notice would force farms to sell at massive losses and wreck the agricultural sector outright. American producers could try to absorb the cost of retaliatory tariffs instead, but at 25% that would still be unsurvivable for many farmers.

It's not clear if Trump understands that, for example, Americans can't really serve cattle feed at the dinner table. Changing the crops a given farm produces takes years of advance planning and infrastructure investment, if it can be done at all. 

Even worse for American farmers, foreign producers will not face the same problems. Because the United States under Trump is starting a trade war with all four of its largest trading partners at the same time, there will be trade barriers against American farmers in all directions simultaneously. But Chinese agricultural producers, for example, will only be restricted in one market, and will find it easier to reach buyers in other countries (including Canada, Mexico and the European Union). 

Likewise, American consumers will see grocery prices go up more than consumers in countries that are not inviting tariffs from all their major trade partners. (Tariffs are taxes and are ultimately paid for by consumers in the form of higher retail prices.)

In other words, Trump is telling American farmers that they have already committed to planting the wrong crops, and that it will be their fault if they can't "have fun" with the resulting chaos. 

Why does this matter?

• When doing something once ended in disaster, it's really stupid to try it again but on an even bigger scale.

• Voters who eat food may not want Trump screwing up the food supply chain again.