Final answer:
An executive order is issued by a commander, such as the President in their role as Commander in Chief, to direct subordinate commanders to execute an operation, and it is treated as equivalent to law unless overturned by courts or subsequent policy.
Step-by-step explanation:
The type of order issued by a commander that gives a directive to subordinate commanders to execute an operation is known as an executive order. In the context of the military, the President, as the Commander in Chief, issues these orders to direct the actions of the armed forces and the broader executive branch. However, such orders must be based on existing authority, such as laws enacted by Congress or powers granted by the Constitution. Executive orders can be significant and lead to dramatic events, as seen in historical examples like the Emancipation Proclamation and the desegregation of the armed forces. They have the attraction of allowing the President to shape policy and direct military and executive actions quickly and decisively.