Maybe I and millions of other Americans are wrong about Japanese cars. Maybe the only thing better about them is the advertising used to sell them. Maybe I don't realize that American cars today are built just as well as Japanese cars. But this is not the point. The point is that as a free individual in a free country I should be able to spend my money on whatever I wish without having to pay any import tax.
Economically speaking, if I were allowed to buy a Japanese car at its true price, say $8,000, instead of the government-imposed price of, say $9,000, I would have $1,000 left. With this money I could buy, for example, a washer and dryer for my family. This would not only make my family's life better (i.e. raise their standard of living) but it would also provide jobs for the washer/dryer industry. Or perhaps I would just put the money in the bank where it would add to the money available to be loaned and thus lower interest rates. If these kinds of actions were multiplied by the millions of dollars spent on import duty taxes by millions of other Americans, the economy of the United States would certainly improve.