Comment by bubblewand

I read that as “when you use them correctly”.

“Correctly” means building consensus so capitalists can expect the new trade framework they're operating under to be reasonably stable, signaling what you’ll do well in advance, then phasing it in, ideally also with a guide to what a phase-out will look like and why or when you would begin doing that. Also, you’d usually avoid tariffing too widely at once. Focused is far more effective.

The stability is needed to get businesses to invest serious money in new buildings, machines, and training, when it won’t pay off for years.

You signal ahead of time and phase them in to minimize damage done. Gives companies time to adjust their stance before the pressure is on.

You focus them on specifically the goods you want to protect, so you don’t also raise the prices of inputs to those goods more than you have to.

You’ll notice zero of those key components were present in this scheme.