An economy is made up of three major sectors, primary, secondary, and tertiary.
The primary sector is agriculture; a nation has to feed itself. The agriculture sector is made up of wheats and grains, fruits and vegetables, meats, nuts, juices, etc. A nation without an agriculture sector will starve.
The secondary sector is industry; a nation has to be able to make things. This sector is made up of metals and ores, chemicals and materials, refining and manufacturing, intermediate and finished products, etc. A nation has to make things to grow.
The tertiary sector is services; a nation has to maintain itself to sustain. This sector is made up of the trade services (electrical, plumbing, A/C, automotive, etc.), professional services (advertising and marketing, sales, information, tourism, sciences, etc. A nation has to service its industry or it will collapse.
Even if agriculture is small relative to manufacturing, it's crucial to survival. It's a primary need.
If China looks to Europe or South America to buy, it will displace the existing markets for those goods because they won't be able to meet China's demand and still feed themselves. They would in turn have to buy from American farmers to make up the shortfall of product that was diverted to the Chinese market.
Trump is trying to realign the global supply chain. The world still needs the goods that are being produced; the demand isn't going away and the current supply will be consumed. It's just going to traverse a different route than before from producer to consumer.
-PJ
Thank you for your articulate response.
Oh bunk. We subsidize them to the tune of $25B a year the little snow flakes. Manufacturing and industry are keys to becoming a 1st world nation. Our founders were all protectionists, every one of them.