Example: US has tariffs on China for steel and aluminum
Chinese state actors were basically giving free electricity to aluminum smelters in China to undercut price in America, that took US's capicity utilization of US's aluminum smelters from high 80s to 70 in one year. And when you drop below 80% capacity utilization you end up losing money as an industry. China was acting in an uneconomic fashion to try to put the US's industry out of business so the US would have a further reliance on China's ability to produce aluminum (strategic values for military and industry).
So Yellen saying "You could save 8 basis points of inflation if you took those tariffs off" is ignorant of national security. He mentioned that if wall street was making decisions we'd all be speaking Chinese immediately, because they make short term decisions for specific profits, and politicians are required to think long term and consider national security.
Kyle Bass' take