I've never understood this... Why not just ban dirty imports and offshore manufacturing? Prices will go up, but at least the money is kept in the economy.
As the majority of what I think I know about international trade comes from reading journalists explaining why the UK is doing Brexit wrong, I don’t actually think I know how big these issues really are — “this molehill is close, those mountains are far away”, to paraphrase Father Ted.
I tend to assume that the epistemic landscape is biased towards those with the cash to influence it and try to weigh against that when considering an issue. With protectionism, it is a little hard because there are certainly domestic industries that benefit from protection.
Now imagine how much money and influence China has and how it can affect our corrupted politicians.