The tariffs would ensnare cutting-edge smartphone and PC-related chips for Apple, AMD and Nvidia if enacted. But Trump is betting his plan will bring more chip production to the US.
The world's largest semiconductor foundry, and one of the primary reasons the U.S. maintains a hold on Taiwan. There are rumours that the US has a plan to blow it up in case of Chinese invasion, that's how valuable it is. So this quite a reversal of strategy.
As I understand it, TSMC and Taiwan themselves have a plan to blow up the foundries should a China invasion look like it's going to succeed. They are already rigged with the explosives from what I understand.
I have heard they are rigged with explosives, but that could just be hearsay. I wouldn't work in a building rigged with explosives. I also don't understand why TSMC would voluntarily self-destruct in such a situation. I don't get the incentive.
Japan used tariffs to increase domestic industries and leap frog into the 20th century. It enabled them to take part in WW II and beyond. That's why you'll see giant corporations that control multiple different industries.
It did work for Japan. The US is in a completely different situation though, and it'll only hurt.
Tariffs can help with preparation, and they are a tool like many other policies. These ones, though, are not thoughtfully planned out. These protect no one, not even the mega-corps who need to figure out how to make everything domestically or price themselves out of the market.
Intel is currently floundering unable to make a good (reliable) node. TSMC can make the chip, but the very important step of packaging needs to be done in Taiwan still.