The theory is fairly simple.

A tariff is a tax on foreign goods. This serves several purposes. Firstly as an incentive for domestic manufacturing. A tariff is an opportunity cost these companies pay for using cheaper foreign labor and bypassing native jobs. Ideally a tariff equalizes out the perverse incentive that is outsourcing.

Secondly it does increase prices of foreign sourced goods. Thereby making local goods more attractive in comparison. The best economies are local ones, self sustaining to the highest degree possible. Because stability matters in economics. The less your supply chain can be disrupted by events outside your control the more secure you are.

I'd also like to point out that the federal government was, prior to adopting Keynesian economics and institution our current system of onerous taxation, almost entirely funded by tariffs on foreign imports.

The Chinese do this too. To a greater extent than even Trump is proposing. To do business there you literally have to create a subsidiary and appoint a Han Chinese man as head of the business, along with yielding your process secrets and intellectual property. The other arguments aside, why on earth would it work for them for the last thirty years but not work for us? Before the cursed Clinton administration lifted our sanctions on them their economic power was pathetic, now they dominate the globe and they did it with aggressively protectionists trade policy.

I answered this before, so I'll paste my answer again because I think it's straight forward.

The tariffs are not going to cause a recession, but you'd better bet your ass that international finance will cause a recession to damage Trump. As for the criticisms you are hearing, they are the Austrian and Chicago School economic criticism of tariffs, so I know what they are doing. You are looking at Syndicalists and Socialists engaging in "Momentary Anarcho-Capitalism."

As a Libertarian and Austrian School guy, tariffs hurt the economy and hurt the tariff enactor more than the person whom you enact tariffs against

... assuming a free market otherwise exists on both sides

If you listen to what Trump's actually complaining about, he's basically saying he will use tariffs as a diplomatic weapon to remove the tariffs that have already been intentionally placed on us. Which would actually be a good thing if he can pull it off. That's not in the framing of this question.

Secondly, he's saying that he'd like to basically move back to a Gilded Age economic and tax system (which means massive de-regulation and de-taxation, replaced with tariffs for income). This would be a huge boon to the economy, as we currently exist in a Keynesian Socialist monetary system which is why the government is such a large share of the GDP. Trump's obsession with President McKinley suggests he wants that to be closer to 1% of the economy. The tariffs won't hurt us if we have a massive free market economy to balance against any problem they create, when our opponents will have massive command economy that won't be able to take advantage of our market.

Third, he is using to push back colonization. A foreign company operating in your borders is not a problem to most of the Chicago School because it comes with implicit assumptions like, "they will hire locals", and "they will be an independent entrepreneur". But these assumptions are false when dealing with Communists and Socialists. What we have seen so far, especially from China's Belt & Road Initiative in Africa is that all Chinese companies are in service to the Chinese Communist Party (no different from any other Socialists ever). The purpose of the corporation is not to make money, but to extend the power of the CCP. They will operate at a loss so long as the CCP can weaponize the lives of 1 billion people to extract all available wealth from and subsidize the corporation and it's operations in foreign territories. They can always out-compete to the detriment of their own economy so that they gain political power. They will hire predominantly chinese foreigners, settle them in the country, then use that colonial population as a political power base in the local government. If they do it a few more times, then they will do it in the state/provincial government. Unfortunately, China aren't the only ones doing this. You'll notice that the government is settling mass migrants in blocs of ethnic group. It's not random distributions, it's 20,000 Haitians in Springfield, OH; not a random aggregate. Having giant blocs of well placed colonies in the US not only guarantees extracted income from welfare that gets turned into remittances, but also political blocs of power within the US. Despite being a failed state, Somalia has a colony in Minnesota and a congresswoman who explicitly stated that her president is the president of Somalia. The point of some of these tariffs will be to stop colonization in the US which are using both American and foreign companies to create political revolution. Again, these are not hypotheses, it's already happened.

I'll put it like this: Thomas Sowell is a Chicago School economist who bitterly complained about Trump proposing tariffs before he was elected in 2016, and explicitly changed his mind on Trump because of how he actually did use tariffs. He changed his mind because he saw what Trump was actually doing. He wasn't having tariffs for the sake of having them because 'foreign product bad'. He was countering monetary aggression and building a gilded age economy. It might not be the perfect Chicago School style that he wanted, or the Austrian School style that I want, but it's a hell of a lot better than the SOCIALIST economy we currently have.

They will cause a recession, because you can't simply jack up tariffs to protect domestic manufacturing when you have no domestic manufacturing in the first place. EVERYTHING in our stores is produced overseas, including huge amounts of our food.

Slowly raising tariffs over time would work, as that would give markets time to renaturaluze the industries we shipped overseas. At that point, prices will better match wages, and our domestic production will be significantly higher quality.

Their huffing about tariffs is moot since the recent push from Congress to go after Temu/AliExpress for "exploiting American customers".

EDIT: I'll put a proper response

The core of where the complaint is coming from, that the prices will certainly increase, is somewhat a legit concern. Because many non-perishable products bought in the US come from off-shore, the economy could hurt briefly to force some companies to bring parts production back onshore. It also would probably mean a soft reset, realigning some prices with the true price, while also forcing companies to have to forgo "disposable" products that should be durable.

For the tax cuts, this would soften the temporary blow to the economy that tariffs could bring and zero out the cost that Americans would have to cover. Then the main issue would be the purchasing power of the dollar as it can't be too low. Also, there are some classes of "essential" items (household appliances for one) that are completely offshore at this point and would probably take months to get all of it back to domestic, as moving and setting up manufacturing doesn't happen in a week. People might wind up paying American prices for Chinese-made junk in some areas. The long-term benefits do outweigh the short-term, but citizens might be unhappy during the transition

The bigger question to me is does this raise the cost of importing something that would obviously never be available in the US (e.g. merchandise from Japan, European cheese, etc.)? Caution should to be given as to what to put tariffs on. If it's Chinese junk, fine, I think people will manage assuming that there aren't many "essential" purchases that have been off-shored. If it's all imports, that's a different story.

Tariffs do raise the cost of goods for the consumer, but it's usually done in the name of preserving domestic industry.

If a company prices a widget at $20 when it's made in America, but can get more profit by pricing a Chinese equivalent at $10, the consumer enjoys the discount. However, that just incentivizes other companies to offshore their production so that they can meet that $10 price and compete, which further drives up the cost of the American made widget and potentially extinguishes the American producer entirely when it can't compete.

The tariff raises the cost of the Chinese widget, and it eliminates the benefit to the producer by offshoring. If it costs the same or more to produce a good overseas, they will produce it in America.

The overall benefits of the economy are additional American jobs, and in some sectors the preservation of industry that would otherwise go extinct. This is particularly important in the defense sector where you don't want to be dependent on a foreign nation for your equipment.

The cost is that you can't get your Chinese shit for $10 anymore but, especially in the case of stuff produced in China, you get what you pay for.

I suspect that many of the price increases will simply be angry leftists hiking prices to stick it to trump.

Tariffs are how the Asian export economies keep imports out from their domestic markets. Japan has done this for many decades, and China does it, too.

Importing a US domestic manufactured car into Japan is a nightmare of red tape and fees, and they do this on purpose, to keep non-Japanese manufacturers out of their markets. If you ever see a Ford/GM/Crysler car in Japan, go buy a lottery ticket, because they are incredibly rare. Last time I was on mainland Japan, around Yokusaka circa 1999-2000, there were two, that I know of: a Corvette and a Grand Am. I'd see them driving around, and they always drew lots of stares, because of how rare they are.

He can make the tariffs however he wants. He doesn’t need to follow the old playbook for how tariffs work.

Don’t fall victim to the libs hysteria about his broken policies. He is playing 5D chess and winning.