The United States was never self-sufficient - ever. It was always a trading nation and trade was the reason it was settled. Initially the US sold raw materials in exchange for finished products. Eventually it sold and traded both. Basic economics states that nearly all nations will have some relative advantage and trading goods of which one has a relative advantage makes everyone richer. Real conservatives understand economics 101 and know that self-sufficiency is a trojan horse rallying cry of the left.
For what its worth, I will admit that the Native Americans were self-sufficient if that is what you had in mind though.
Not self-sufficient, no. But there were always varying levels of tarriffs, to protect domestic industries. And there were always arguments about how high those tarriffs should be. But it was agreed that the U.S. should be self-sufficient in essentials, and in whatever was needed for defense, even if they had to stockpile some materials.
Complete elimination of tarriffs was something new, and it destroyed numerous industries, such as the clothing makers, TV makers, steel mills, and so forth.
I don’t argue for complete protectionism. But some level of protection is necessary, especially when so-called “free-trade” is really a one-way street, in the other direction.