There's no coherence here, the people coming up with this policy are either ignorant or incompetent to the point of malice (Navarro, AKA "Ron Vara," being the benchmark). Tariffs, when used judiciously, can help support "infant industries" where domestic investment in emerging technologies means that supply constraints are less of a concern and where there are long-run expectations of lower domestic prices through efficiencies. In some cases, targeted punitive sanctions (against dumping policies, or to enforce labor and environmental standards) make sense, but the economic evidence on efficacy is mixed.

There is somewhat of an argument that countries such as China overuse American consumption as a crutch for development, rather than stimulating domestic consumption (Xi has, to give very mild credit, proposed policies to increase domestic demand); tariffs would certainly force countries and trade blocs to focus on non-American consumption, though this is a bit like losing weight by removing the patient's esophagus.

What we're seeing here is just ridiculous, from an economic perspective. Low-cost low-margin manufacturing is not coming back to the US, absent an economic crisis that pushes down to a upper-middle-income-level state (stay tuned!), while putting tariffs on agricultural products simply ensures that consumers will pay more without a corresponding increase in domestic competition (how many pineapples does the US grow?). The "calculation" of the tariffs, such as it is, is simply a tax on comparative advantage, which is mercantilist nonsense we left behind centuries ago. There's no steelman for this; even if there were, the increase in raw material costs would make the steelman unaffordable for us both.