So it's probably worth giving a bit of historical background on how we got here as well. And to be fair a lot of this is applicable to the UK as well.
After WW2 the US was the dominant world economy, this continued up until the mid 70's due to the energy crisis and competition from other countries.
The US manufacturing industry started to get growing competition from Japan and Korea. This was a precursor to what would follow with China.
The Communist Government in China seeing the economic collapse of the Soviet Union recognised it needed to massively grow the economy if they were going to stay in power.
This picked up in the 1990s and what really changed things was that China was admitted to the WTO in 2001 meaning it could export to other countries with much lower tariffs.
Because wages, safety standards, working conditions and environmental controls were much much lower in China plus they had cheaper but dirtier coal fired electricity, China could manufacture basic goods a lot more cheaply than the US. The flip side idea was that the US would sell back to China high value services and complex manufactured goods.
This was great news for the US consumers who could now buy clothing and manufactured goods (often through Amazon) at much lower prices which kept inflation really low.
The downside was that US workers in manufacturing etc could not compete with cheaper Chinese imports so they lost their jobs. The idea though was that the US would upskill those unemployed into more complex manufactured goods. Incidentally this same idea was what pushed the Blair Government to rapidly increase the number of young people going to University in order to upsell them.
Unfortunately it proved a lot harder to upskill an unemployed steel worker into a jet engine engineer or a textile worker into a software engineer. As a result these people stayed unemployed and were basically thrown on the societal scap heap but hey the rest of us could still get $3 t shirts and $ 50 DVD players.
Politically what has happened is that those forgotten unemployed or under employed workers that were thrown on the societal scrap heap got increasingly pissed off and through social media became increasingly further right or further left.
Which then leads us to politicians like Trump appealing to these people with slogans such as Make America Great Again".
The idea of the tariffs is to bring back manufacturing and jobs to the US. It is very much a gamble whether this comes off or not but being kind and assuming it does then the upside will be more jobs and the downside higher prices for a lot of stuff. Or more simply shifting the focus more towards workers and less towards consumers.