I really do not understand his reasoning with regards to tariffs. He says there will be blanket minimum tariffs of 10-20% on all imports. He says that the tariffs will push Americans to buy American products. For that to happen, the import needs to become relatively more expensive than the domestic product. When asked, he says that the importer will absorb the cost of the tariff, meaning that US consumers will not pay more for the imported product. There will therefore be no financial incentive to by the more expensive American equivalent.
He additionally says that the tariffs might enable him to do away with federal personal income taxes. If the purpose of the tariffs is to encourage consumers to buy American, it follows that imports will fall, and thus, federal income will fall. Granted, corporate tax revenue might increase, but he had promised to reduce corporate tax rates. And his tariffs will see retaliatory tariffs which will harm US exporters (lowering corporate tax revenue further).
The guy is a moron.