Earlier quoted context omitted.
The tariffs this time are far in excess of anything he did previously or promised to do while running for office again and took nearly everyone by surprise though.
This pre-election BBC summary - https://www.bbc.com/news/articles/cwy343z53l1o - pretty clearly spells out what has eventuated, describing it as a "central campaign pledge": > Trump has made tariffs a central campaign pledge in order to protect US industry. He has proposed new 10-20% tariffs on most imported foreign goods, and much higher ones on those from China.
That uncertainty makes it very hard to manufacture goods or buy raw materials.