Since it seems to be a hot topic lately, I figured I'd educate myself. Just read 3 pretty decent books about it.

Tariffs - History, Purpose and Outcomes. Daniel Bulmez

Tariffs and Trade Wars - A Historical Analysis of Protectionism. Alexander Masters

No Trade is Free: Changing Course, Taking on China, and Helping America's Worker's. Robert Lighthizer.

I've finished the first too. Good historical context and foundation to help you understand Tariffs. I'm about 2/3 way thru the last one.