Americans would want to have high value-added activities done in the USA, and low value-added activities done abroad. Tariffs are being marketed as trying to achieve that goal.
The five strategic areas/sectors identified as a priority for repatriating activity into the USA are pharmaceuticals, forestry, steel/aluminum, automobiles, and semiconductors.
How is forestry a high value added activity? Are we including furniture manufacturing, or maybe residential housing construction in that sector?
Are we including all of the byproducts of steel and aluminum in the steel/aluminum strategic area? I assume it's not just the raw materials?
Is software included as part of the semiconductor sector?
The bull case for the USA is 1. Reshoring actually happens 2. Other countries actually drop their tariffs/trade barriers 3. A new golden age of Pax Americana/free trade ensues, with Americans exporting their high value manufactured goods worldwide
The bear case for the USA is 1. Republicans get hammered in the midterms 2. Entire world raises tariffs against the USA 3. American factories close en masse 4. USA dollar is devalued and reserve currency status is threatened
Historically, the pattern seems to be: 1. Acquire global empire 2. Promote free trade inside that empire, benefiting high-value added domestic activities and limiting high-value added activities in areas outside the core of the empire 3. Run out of money due to the costs of fighting wars to maintain the empire 4. Military power declines 5. Through one or more wars, another power takes over
Proponents of tariffs argue that Trump is trying to take us back from Step 3 - run out of money to Step 2 - promote free trade. In order to understand this thinking, it's important to understand that your empire's colonies aren't supposed to be allowed to promote their own industries and limit free trade by enacting duties on your own high value exports. To enforce free trade, you then fight wars, you can send gunboats (Opium Wars) or invade (Gulf War). But you can't invade and fight everyone, and rising powers protect their own industries through various measures as they build up.
But power is most powerful when it's not used. The threat of action is much more powerful than the actual action. That's why I'm more than surprised and not too happy that tariffs on a large scale have actually gone forward. Ideally, the threat of tariffs would be used to actually cause other countries to drop their tariffs, and free trade ensues. I'm not sure about historical examples of this working for getting other countries to drop their tariffs. You could certainly try suppress the growth of other countries, I'm not sure how well that works in a global marketplace scenario.
The flip side of that is that if you threaten for too long and never actually do anything you may lose some credibility. But I don't think anyone is arguing that the Americans are gaining credibility by enacting tariffs. It's a big world, and unless Americans have the power to influence their trading partners not to trade with others, then everyone can just trade with each other instead of trading with the Americans.