Item in US costs $10 to sell.
Same item made abroad and shipped to US costs $8 to sell.
The result is the manufacture of the US item is undercut, and the manufacturing moves abroad because it can't compete with cheaper products.
Well designed tariffs, at least, equalize the cost to the consumer so the items cost the same.
Now, the US manufactured item is sold competitively, and there is less of an incentive to move the manufacturing of that item abroad.
Please, enlighten me, how am I wrong? Are you going to say that there will be reciprocal tariffs put in place so that US manufactured items can't compete with foreign manufactured items abroad? Well, I don't see why our merchant marine should be protecting and maintaining those foreign countries' trade, then. Or why we should be acting as the de facto national defense for many of those countries. Or why we should be providing billions in foreign aid, giving their youth carte blanche educational visas to attend our premier universities, or any of the other things that are of massive financial benefit to them.
Excuse mistakes and oversights out of tiredness.
What tariffs do is grant a quasi monopoly and, generally, a monopoly price on domestic firms.
Let's make things more tangible and say that the item in question is... toothbrushes. Let's say a toothbrush costs $10 to sell in the US, but a toothbrush made abroad and shipped to the US costs $8, okay? I'm thinking of toothbrushs as an example because they don't really have substitutes.
So, what tariffs do is injure the consumers within the toothbrush business, who are prevented from purchasing from more efficient competitors at a lower price. Also injured are the more efficient foreign firms and the consumers of all areas, who are deprived of the advantages of geographic specialization.
In a free market, what would happen is that the best resources will tend to be allocated to their most value-productive locations. For instance, you wouldn't produce oranges in Antarctica. Blocking interregional trade will force factors to obtain lower remuneration at less efficient and less value-productive tasks.
It is logically necessary and inevitable that consumers are being exploited by tariffs. Every attempt to debunk or disprove this is futile.
To prove to doubters that pro-tariff arguments are absurd, let's carry the idea of a tariff to its logical conclusion - interpersonal tariffs.
Let's take two individuals, Josh and Matt.
And before you object that this is invalid, the same qualitative effects do take place when a tariff is levied on a whole nation as when a tariff is levied on one or two people, the difference is merely one of degree. Like, the impact of a tariff is clearly grater the smaller the geographic area of traders it covers. A tariff "protecting" the whole world would be meaningless, at least until other planets are brought within our trading market.
Okay, so, suppose Josh has a farm, "Kiwi Farms", and Matt works for him. Loving pro-tariff ideas, Josh exhorts Matt to "buy from Kiwi Farms". "Keep the money in Kiwi Farms", "don't be exploited by the flood of products from the cheap labor of foreigners outside Kiwi Farms", and similar stuff.
To make sure that this aim is accomplished, Josh levies a 1000% tariff on the imports of all goods and services from "abroad", from outside the farm. As a result, Josh and Matt see their leisure, or "problems of unemployment" disappear as they work from dawn to dusk, trying to eke out the production of all the goods they desire. Many things they desire cannot be produced at all, others can be produced with centuries of effort.
The promise of protectionists, "self-sufficiency" boils down to the "sufficiency" being bare subsistence instead of a comfortable standard of living. Money is "kept at home" and they can pay each other very high nominal wages and prices, but in terms of goods, they find that the real value of their wages plummets drastically. The tariff principle logically amounts to the situation of isolated or barter economies, think Robinson Crusoe and Friday on the island.
The tariff principle is an attack on the market, and its logical is the self-sufficiency of individual producers. Which, if followed consistently, would be poverty for all and death for most of the present world population. A regression from civilization to barbarism.
Now you're saying "but we don't do 1000% tariffs", but a mild tariff over a wider area is a push in that direction, and the arguments used to justify the tariff apply equally well to a return to the "self-sufficiency" of the jungle. Sure, most tariff enjoyers will avoid avoid pushing the argument this far because it is very clear that all parties lose drastically. With a milder tariff, on the other hand, the tariff-protected "oligopolists" may gain more (in the short run) from exploiting the domestic consumers than they lose from being consumers themselves.
Ironically, Henry George, who was wrong about many things, was sorta right about tariffs.
To quote:
Protection implies prevention. [...] What is it that protection by tariff prevents? It is trade. [...] But trade, from which "protection" essays to preserve and defend us, is not, like flood, earthquake, or tornado, something that comes without human agency. Trade implies human action. There can be no need of preserving from or defending against trade, unless there are men who want to trade and try to trade. Who, then, are the men against whose efforts to trade "protection" preserves and defends us? [...] the desire of one party, however strong it may be, cannot of itself bring about trade. To every trade there must be two parties who actually desire to trade, and whose actions are reciprocal. No one can buy unless he finds someone willing to sell; and no one can sell unless there is some other one willing to buy. If Americans did not want to buy foreign goods, foreign goods could not be sold here even if there were no tariff. The efficient cause of the trade which our tariff aims to prevent is the desire of Americans to buy foreign goods, not the desire of foreign producers to sell them. [...] It is not from foreigners that protection preserves and defends us; it is from ourselves.
Think about the long run effects of tariffs.
If you think the immediate beneficiaries of a tariff will benefit in the long run, remember that only firms within an area are "protected", but ceteris paribus anyone is permitted to establish a firm there, even foreigners. That means that firms from within and without the area will flock into the protected industry and the protected area until the monopoly gain disappears, although what remains is the misallocation of production and injury to consumers.
Regarding your last questions, quick answers:
> Are you going to say that there will be reciprocal tariffs put in place so that US manufactured items can't compete with foreign manufactured items abroad?
Every tariff means injuring the local/domestic consumers. Therefore, "reciprocal tariffs" are nothing but contests in who is more willing to shoot themselves in the knee.
> Well, I don't see why our merchant marine should be protecting and maintaining those foreign countries' trade, then.
I am not advocating for that. "Your merchant marine" shall do what it finds reasonable to do as long as it respects the rights of peaceful people.
> Or why we should be acting as the de facto national defense for many of those countries.
Again something I am not advocating for. You do you.
> Or why we should be providing billions in foreign aid, giving their youth carte blanche educational visas to attend our premier universities, or any of the other things that are of massive financial benefit to them.
Again something I am not advocating for. Foreign aid should be abolished.
