What economic thinking went into the Trump tariffs announced last week? None at all. In fact, the economists (“economists”?) who currently have his ear seem to regard their job as being to confirm the wisdom of whatever he decides to do. Peter Navarro:

My function, really, as an economist is to try to provide the underlying analytics that confirm his intuition. And his intuition is always right in these matters.

Translation: Navarro sees his role as that of a propagandist, not a source of independent advice.

But the rest of us don’t have to accept that Dear Leader is always right. And in fact, these tariffs are weirdly poorly considered even if all you want to do is create manufacturing jobs, leaving aside all the other ramifications.

Why? Because steel and aluminum aren’t final goods – nobody directly consumes steel. Instead, they’re intermediate goods, basically used as inputs to other U.S. manufacturing sectors. And while tariffs that raise primary metal prices may increase production of those metals, they make the rest of U.S. manufacturing less competitive.

Trade economists used to talk about this kind of thing a lot. Back when most developing countries were trying to promote manufacturing with tariffs and import quotas, we used to talk about effective protection, which depended on the whole structure of tariffs. Sometimes effective rates of protection were very high: if you imposed, say, a modest tariff on cars but none on imported auto parts, the effective rate of protection for auto assembly could easily be in the hundreds of percent. Sometimes, however, rates were negative: if you put a tariff on parts but not on cars, you were actually discouraging auto assembly.

Clearly, we can apply this kind of analysis to the Trump tariffs. In fact, there are people out there trying to put numbers on it, although I wouldn’t put too much weight on them, for reasons that will be clear in a minute.