(Sorry all - I decided to edit my post.)
First - Ronald Reagan hated the idea! In a 1988 speech, President Ronald Reagan strongly opposed tariffs against Canada and Mexico, calling them anti-American. He emphasized the importance of free trade, stating:
"Our peaceful trading partners are not our enemies; they are our allies. We should beware of the demagogues who are ready to declare a trade war against our friends, weakening our economy, our national security, and the entire free world—all while cynically waving the American flag.
The expansion of the international economy is not a foreign invasion; it is an American triumph—one we worked hard to achieve and something central to our vision of a peaceful and prosperous world of freedom. After World War II, America led the way in dismantling trade barriers and creating a global trading system that paved the way for decades of unprecedented economic growth.
Yes, back in 1776, our Founding Fathers believed that free trade was worth fighting for. And we can celebrate their victory because today, trade is at the core of the alliance that secures peace and guarantees our freedom. It is the source of our prosperity and the path to an even brighter future for America."
EG: Australia had tariffs for decades. It delayed us all being able to afford colour TV's for about a decade after everyone else got them.
Second - tariffs limits the economies of scale your producers can achieve to just your country. China doesn’t have Henry Ford’s production line - they’ve shot way past that! China has production line cities! Where they build another CITY depends on what the ‘production line’ in that area needs! 2 or 3 million people will suddenly live in the next ‘node’ of whatever that industrial region of China is building!
Third - there’s no way the western world can compete with that - but do we want to be dependent on China when they’re eyeing off Taiwan? Do we want to buy EVERYTHING from China when we could end up like Germany asking Putin to “Please sir - stop invading Ukraine. Also - here’s our gas bill - please don’t cut off our gas!” The only answer? Friend-shore! That is - have completely free trade amongst a club of democracies. It will still not be as cheap as Chinese stuff - but it’s at least better than trying to go it alone! Trade means I sell you the cheapest stuff I can make - and you do the same for me - and we both get richer by having more money in our pockets by sharing our cheapest stuff. But instead, Trump has this false belief that tariffs will fix everything - and has in effect hurt the entire western world in our competition with China. He has betrayed the western democratic world in our security, economies, and in principle. The west is over!
Fourth - some sectors require vastly more 'economics of scale' or concentration into one specialised company than others. Of course - I'm thinking of PC chips. The whole PLANET has decided to outsource production of super-high-tech, super-small nano-chips to Taiwan. Just one fabricator of an ordinary chip is maybe a third to half a billion dollars. When you get down to the bleeding edge - the cost gets crazy expensive!
Estimated Total Cost of a 3nm Chip Fab: $15–$20 Billion - so the only way it can be profitable is to run all day and all night - trying to meet the
global needs for the most advanced chips at a high price per unit. America only has 5% of the world's population (yet for decades has burned through 25% of the world's oil!). Americans have felt entitled to the latest and greatest tech whenever they want at affordable prices. Tariffs will undermine this. Critically! And if someone just waves the magic words around "Oh - we'll have to SUBSIDISE IT!" - I thought the whole point of this exercise was to MAGA - to help the American economy to recover and pay off debt - not increase government spending!