Then, maybe, China's comparative advantage goes away. Then Walmart might have to look elsewhere for their cheap junk. Then, maybe, they will have to look to domestic sources to manufacture their cheap junk.
Comparative advantage between trading partners is great when those countries are similar in economic terms. When one country's labor costs are a tiny fraction of the other's it doesn't take a genius to figure out what is going to happen.
Look at North American trade. The FTA between Canada and the US worked out very well because labor rates and other economic metrics were similar. When Mexico was included in NAFTA all hell broke loose because Mexican labor rates sucked the life out of manufacturing.
The next argument from you will be that a tariff on Chinese goods will initiate a trade war that will presage a global depression. We are already on the cusp of a global depression. Erecting tariff barriers will not change that.
North America is a far different place in 2015 then it was in 1930. We have lots of clean air and clean water. We can feed ourselves. We have plenty of energy in all forms. Can Japan say that? Can China? We can survive if trade collapses. We can actually make everything we need and still feed ourselves. Can China?
I'm not saying a depression wouldn't be bad, it just won't be as bad here as in Asia or Europe.
What domestic sources?