As American's we have sort of a "Free Market" tendency. So private companies, by default, can deal and trade with whomever they choose. It's only when laws are passed that do not allow the sale of good & services between certain parties are restrictions imposed.
In order to stop ALL trade with china, the USA would have to impose laws that forbid purchasing anything from China, like what we did with Cuba.
And thus, putting Amazon and WalMart out of business, adding 100 bazillion people to the unemployment figures.