Let’s take a single example.

This is nickel, a ferromagnetic metal. It’s used in all sorts of applications from stainless steel to batteries to electroplating
Now, Canada has very large reserves of nickel. It used to produce about 80% of the world’s supply, and it still has about 2.2 million tons of reserves. Indonesia currently has the largest reserves at 55 million tons.
And here’s how much nickel Canada produced per year.

Now, look at that 2016 figure – about 220,000 tonnes (metric, a little more than a ton).
Total U.S. nickel reserves – are 300,000 tons. That’s less than two years of typical Canadian production.
And a lot of Canadian nickel goes to the United States. Because we have it, and the United States doesn’t.
And that’s not the only thing. Canada has roughly eight times the amount of uranium the United States does.
And sometimes, even with tariffs, it might be cheaper to source from Canada. For example, auto parts are made in Canada because one of the highest labour costs for American producers is “health insurance”. The people who make auto parts are highly skilled, unionized, and can get what they ask for because they take years to train and work on tolerances to the micrometer level.
Before the last election, Republicans were whining about “worker shortage”.
Such a strange way to complain about having “too many jobs”!
Elon said he needed more visas to import foreign workers to fill job openings.
But now we are spending hundreds of billions of dollars to create more jobs, when unemployment was already low and struggling to find enough workers to fill the jobs already open.
All we need to do to avoid tariffs is get rid of the idiot who keeps creating them.

What do you need in order to produce a product?
1.) Raw materials. We don’t have all the raw materials for every product, or we might need more factories to make them first. Say making shoes—ok, but first we need a lot more leather tanneries. That will take time to build up.
2.) Factory facilities. Obviously we don’t currently have the capacity to replace all this right away:

So we have to build new factories. Rivian company is building a new factory in Georgia. It will take two years to get it up and running.
3.) Workers. Our unemployment level is only 4%, and not everyone is going to want to work in a factory.
4.) So we’re going to need more immigration! Factories in the US have *always* been staffed mainly by immigrants, whether from Quebec or Poland.

Does your daughter or sister want to work at this job?
5.) *Everything* will have to cost more!! Why did companies start manufacturing overseas? To save money. US workers cannot and will not work for $1 an hour, while people in Bangladesh might have better lives at that rate of pay.
6.) Some products cannot be grown in the US. We have no banana farms, or tea plantations, and coffee is only produced in very small (and expensive) quantities in Hawaii. You will only be able to have whatever fresh products are available in season. No strawberries in winter. No apples in early summer. Very few avocados ( Imported avocados now account for 90% of the domestic supply)—and you first need to grow an entire tree!
7.) Some products are superior in certain countries. Yes, we make wine and cheese and olive oil and soy sauce and spirits—but people like French champagne and Italian cheese and Spanish olive oil and Japanese soy sauce and Scotch from Scotland. No more of any of that.
8.) Ever been to an ethnic grocery store? Shut them all down—no more Japanese products or Chinese products or Italian grocery stores, or German sausage.
As long ago as 1776, Adam Smith wrote a book called The Wealth of Nations, in which he explained that different places have different specialties, and by trading, everybody is better off.
Too bad Dear Leader never read it.