Economic power can be generaly defined as the ability to control or influence the behavior of others through the deliberate and politically motivated use of economic assets. National economic power implies that a government is in a position to use, offer, or withhold such assets even when they are in private hands (for example, by mandating trade embargoes or imposing controls on exports to targeted countries). In fact, the exercise of economic power may well have economic costs because almost by definition it entails interfering with decisions made for economic reasons.
Economic power can also be thought of as the ability to resist external control or influence because dependence on external suppliers is sufficiently diverse to preclude vulnerability to outside pressure. Ghana, for instance, imports about 80 percent of it rice from foreign sources and is thus vulnerable to rice exporters as a group (although not to any one country). But what is sometimes forgotten is that sellers need markets. If Ghana was to significantly reduce its appetite for foreign rice it would gain relative economic power over these suppliers. Persuading others to establish a "consumer cartel," as some have suggested, would have an even greater effect on the balance of economic power.
An extreme example of the ability to resist external control is economic self-sufficiency. Certain great empires of history, such as imperial China, were almost entirely self-sufficient. But in today's world, the pursuit of economic self-sufficiency results in lower levels of technology and productivity and a greater degree of poverty than would otherwise be the case (North Korea is a perfect example). If market forces are allowed to operate, some countries will be more self-sufficient than others, but none will be completely self-sufficient in all sectors.