[Brian_K_White]

You can't turn farming capacity on and off. If you need a given level of capacity, it has to already be there up & running, the entire system including all the people filling all the roles with all the experience, and all the machinery, all the distribution and economic relationships and countless support dependencies.

What you CAN do quicker is change what you use that capacity for.

And even what you do with the current product right this moment even before you have time to change what you will harvest next year. Corn that that is normally only fed to animals is still absolutely a ready resource for people if they need it. Most of our food is fully artificially constructed out of base ingredients these days. Every box and bag and can on the shelves that needs a carbohydrate barely cares at all where it comes from or what it originally tastes like raw.

[sfink]

That can explain a little. Not the 40% of all corn grown that is used for ethanol.

Which would be better for the nation's security? Having all this ethanol, or having 31x the energy provided by that ethanol via solar production? We couldn't actually use that much solar power right now, but that's part of the opportunity cost: we aren't gearing up to make use of it because we're generating all of this ethanol that we don't need instead! The capacity maintenance argument works both ways: pay to maintain the capacity to grow vastly more corn than we'll ever need, or pay to maintain the capacity to generate tons more energy that we're far more likely to need.

(Also, taking land that has been largely destroyed by industrial corn farming and changing it into land that's growing some more valuable food crop isn't just a matter of changing your mind about what to grow the next year.)

[triceratops]

But what is this system trying to secure against?

America already grows enough animal fodder without counting corn for ethanol. If some calamity strikes corn production for animal fodder, it will equally affect corn production for ethanol. Because it's the same crop.

And also why can't you scale farm production up and down? It isn't like manufacturing and factories. Preserve farmland and produce enough for the country's consumption needs. That'll keep farm labor and machinery sufficiently busy. It also prevents the waste of fertile soil growing food that's never eaten.