A fundamental principle of economic liberalism is that competition drives improvement and lowers costs, while also promoting economic growth.
Economic nationalism runs counter to this.
However, it isn't quite that simple because there are two important words that need to come before "competition" and that is "free and fair".
Which is why we have trade agreements. However, for all of the above conditionality, historical experience is that international trade drives growth and economic nationalism restricts it.
Apropos the USA, in the 1970's it took European and, even moreso, Japanese car makers to force US Automakers to wake up and raise what had become utterly appalling quality and efficiency standards. Just one example...