[starky]

>Why on earth are we trying to bring it back?

The main argument would be if you are relying on other countries and you can't produce anything yourself then you need to rely on other countries being good trading partners. If the relationship with those trading partners fails your economy is in trouble.

[hombre_fatal]

What does that actually look like, though? And at what cost?

No single country can produce everything it currently imports much less compete globally on every product.

Does the government just prop up every industry with subsidies? Or use tariffs to make everything as expensive as domestic goods?