Coherent single explanation
Tariffs work as follows:
1) A POP does not pay the tariff surcharge at all, so far as I can tell. Goods remain at the same price for POPs regardless of your tariff rate.
2) You only get tariff money on goods that POPs actually buy. The income is based on the price of the good bought. Thus, poor POPs who are being taxed will only buy grain and wool, netting you little or nothing in the way of tariff income.
3) Further, you do NOT get tariff income on a purchase if a POP buys a good you have produced domestically -- hence, producing something cheap like grain doesn't hurt you much and indeed makes sure your POPs get some of their subsistence goods, but glass and especially clothes and liquor cut your tariff income DRASTICALLY.
4) Conservative and protectionist POPs are relatively unbothered by tariffs, but clerks, craftsmen, socialists, and liberals all have very significant consciouness increases when high tariffs are in place.
So...taxes bad, tariffs good, until you industrialize.
-Adso