>The United States will be an autarchy, similar to how LaTam was in the 70's, when tried this exact idea. The tariffs being as high instantly, will impact the economy, later, the country will probably grow, which is what they expect, but this is not a productive grow. Because your new factories now are not competing with external products, so your productivity go down, this means real income will also go down.
If what you say is true, tarrifs should not exist in any country. And yet, most countries are using tarrifs.
What if a particular country is using dumping and sell at prices so low, it will kill a particular industry? And after they kill it, they start jacking prices at unseen levels and you will have to pay because you don't have a choice?