KNOXVILLE, Iowa — Today President Trump is visiting Dubuque, Iowa, where every year at harvest time, millions of tons of grain come via rail and truck to be loaded onto barges on the Mississippi River and shipped to Mexico, China and much of the rest of the world. Harvest puts coin into the hands of farmers, and they and their communities — indeed all of America — profit. Not this year.

The president is here to trumpet a $12 billion plan to aid American farmers. Why do they need aid? For Iowans, it’s because 33 percent of our economy is tied, directly or indirectly, to agriculture, and Mr. Trump recklessly opened trade wars that will hit “Trump country” — rural America — hardest and that have already brought an avalanche of losses. Indeed, the impact of his tariffs will probably be felt by family farms and the area for generations.

So perhaps visiting Dubuque is the least he could do.

The cost of being shut out of overseas markets for soybeans, beef, pork, chicken and more will be in the billions. Once those markets are gone, they will be difficult to recover. Commodity prices continue to drop, and good weather suggests an excellent crop is in the making, which will drive prices further down.

Brazil is ready to step in with increased soybean production, and China has already shifted its purchasing power there.