Which economic theory suggests that a nation becomes wealthier by making others poorer?

The economic theory that suggests a nation can become wealthier by making others poorer is Mercantile Theory. This theory, which was prominent from the 16th to the 18th century, posits that the wealth of a nation is best served by accumulating gold and silver and maintaining a favorable balance of trade. Under this theory, nations believed that economic growth could be achieved at the expense of other nations. By exporting more goods than importing, a country could increase its stock of precious metals, which were seen as a measure of wealth.

This view led to various policies aimed at restricting imports and encouraging exports, often resulting in exploitation of colonies and trading partners. The focus is on a zero-sum approach to wealth, where one nation's gain is directly linked to another's loss, which is a cornerstone of Mercantile Theory.

The other choices do not align with this idea. Equal Trade Theory suggests mutual benefits in trade relationships, Armada System does not specifically pertain to economic wealth in the same sense, and Machine Theory typically refers to the impact of mechanization on production and labor, rather than wealth redistribution among nations.