President Trump (and other protectionists) like to frame international trade as a context: the domestic nation is competing with foreign nations and that imports must necessarily harm and exports necessarily help. Aside from the numerous logical and mathematical issues with this interpretation, it is economically incorrect from the perspective of competition.
International trade represents the exchange of goods and services across political borders by individuals. More simply put, it involves buyers on one side of an arbitrary line and sellers on another. The fact this is buyers and sellers matter for a simple reason: buyers and sellers do not compete with one another. They cooperate.
Buyers compete against other buyers. Sellers compete against other sellers. Buyers and sellers do not compete with one another. The seller must offer a price acceptable to the buyer. The buyer must offer a price acceptable to the seller. The two will cooperate to make the exchange happen (or else they go their separate ways and other buyers and sellers step in). What this indicates for international trade is this: when foreign producers are harmed, either through tariffs or quotas, they are not the only ones harmed: their domestic customers are harmed as well. When Trump mentions “punishing” foreign companies for having the gall to offer Americans the best possible deal, what he is actually talking about is punishing Americans by reducing their options and preventing their cooperation with other people.
If we are to use the (highly misleading) language of nations trading with one another, this means that international trade is not a competition but rather cooperation. It is impossible for one nation to be losing at trade because there is no competition! Buyers and sellers cooperate. When two nations trade, they cooperate.