of "conering" you forget about capital. For example, if China decides to subsidize its steel industry to drive our steel industry out of business, for Americans at large that would be only a benefit (as long as US government does not tax property much.) After few years of such subsidizing, the wealth will be transfered from China taxpayers to American consumers. US dollars that went to China would come back into US other industries that compete well thus creating more jobs (China has no capital to subsidize all industries.) Without taxes on property, US steel industry (mothballed for time being) can resume while China would be without capital. Sacrificing all Americans to secure jobs for labor in steel industry will only make all Americans more poor.
If you want to secure jobs for all industries, you need socialism and stagnation - equally poor. China indeed tried that.