Earlier quoted context omitted.
The issue with the tariff approach is that they generally apply to countries that actually have an auto industry, but not all countries have one. Countries without tariffs will enjoy lots of competition and cheap prices, while established automakers with tariff protections will be squeezed out. I don't see how it's possible to stop China, even if rich western countries band together.
The problem is when it's not fair competition. Certainly Tesla has received government subsidies, but I expect their numbers to pale in comparison to whatever money the Chinese government has directly and indirectly poured into BYD. Flooding foreign markets with your heavily-subsidized cars in order to kill your competition is great for you, but not so great for competitors in the market of sale.
The subsidies are more interesting. When does legitimate assistance become a subsidy? Eg if Biden/successor invests in domestic lithium mines, is that a subsidy? If they offer buyers $x rebates, is that?
Looking at the last example, if BYD said to a US buyer, "this car is $x but we'll give you a rebate", that would seem to be just as fair as Uncle Sam offering one. The objection would seem to be that it was the Chinese government acting as the source of cash.
I suggest that the answer is that noone should offer direct purchase subsidies, but government can offer whatever investment they like to support their industries. I cant escape a feeling that the US and European car industry are crying foul because (despite Musk's attempts to drag them into the future) they havent figured out how to make electric vehicles profitably.