And that's a quite good thing. Bringing back an industrial base to the US. I have no idea if the tariffs will do to the economy as a whole, but I can't disagree with Trump that domestic steel production is a national security issue as well as an economic one.
I see it both ways. I understand having a means of production in the event to go on a war footing, but question the why tariffs are needed at this particular time. In the event that we did need to ramp up production, why wouldn't Canada and Mexico be of assistance (at least formerly)? The idea that we would need to ramp up production necessitates a fairly large conflict, approaching a world war. It's difficult to see us in that type of situation where both Canada and Mexico, were at a minimum neutral, and at worse hostile. And if the latter were true, there's no force in the Americas that could prevent us from either extorting or outright taking those means of production... and this doesn't account for how quickly we could convert domestic steel, used for other purposes, to military functions.
The Trump tariffs, on the whole, I think are a very bad thing. It seems more likely we will enter into that long overdue recession, with none of the traditional means to pull ourselves out of it quickly (thanks to the tax cuts). If we hit a particularly bad economic downturn, that recession could easily turn into a full blown depression. It appears, at least to me, that we are being given short-term benefits for political gain, without looking at the long-term negative consequences.