The instrumental character of power is that of a "means to an end." It includes the tools, resources, and abilities used to pursue goals. The meaning of power and its role in politics is understood first with a background of its dual nature.
De jure refers to the theory of power. The concept of "absolute power," considers tangible factors. When comparing nations' power, money and gross national product are units of measure; the United States is more powerful than Mexico. Army size and strength are also measurable. World powers, such as the U.S., Britain, and Japan, defeat countries with smaller, weaker armies. From an objective standpoint, tangible assets make a country a world power. But world powers and their leaders also possess intangible qualities.
De facto is the subjective aspect of power that is immeasurable. Charisma, such as that of Mahatma Gandhi and Martin Luther King, could not be described, but made them successful leaders. The "will to win" or morale of people, especially athletes, is power. De facto power is continually changing because of the relative character of power, to time, situation, and contending parties. When power is applied in interaction with contending parties, the situational factors of power and politics come into play.
Power is initially proven in a political situation through credibility. The opposing party's belief that you have power and will use it makes them take you seriously. It makes them respond to you, and the interest you are pursuing. For example, the United States wants more oil production from the OPEC nations. The U.S. has power, as mentioned before, and credibility based on its world power status. OPEC's response will be based on this credibility along with the U.S.'s capability.
What the United States has and can do reestablishes the country's de jure power. OPEC's oil-producing countries, such as Saudi Arabia and Iraq, know the U.S. has a strong army. But...