Rules of engagement (ROE) determine when, where, and how force should be used. They are valuable in that they standardize the rules of conduct in war situations. This standardization not only helps the military to perform more effectively, but it also allows non-military government officials to coordinate policy and strategic planning, since the rules are formulated on a series of realistic scenarios.
There are few key concerns on which military rules of engagement are based. The primary one is the circumstances around which force should be used. Other concerns are against whom military force should be demonstrated and the extent of force that should be shown.
In addition, there are two types of errors that can occur with the rules. The first, known as Type I, occurs when the amount of force that can be shown is restricted to the point that it prevents objectives from being achieved. Excessive force is known as a Type II error.
An example of a Type I error is the crisis faced by the United Nations Assistance Mission in Rwanda (UNAMIR). Present in Rwanda from 1993 to 1996 and consisting mostly of Belgian soldiers, the UNAMIR intended to implement the Arusha Accords to stabilize peace between the two ethnic groups in Rwanda, the Hutus and Tutsis. At the onset of civil war between the groups, however, UNAMIR troops, due to restrictions within the UN charter regarding the rules of engagement and the peaceful purpose of the mission, had to turn their weapons over to rebel forces as they were besieged by fire for over two days. Instead of restoring peace, the United Nations could not prevent the Rwandan genocide as it faced a shortage of troops. Belgium withdrew its troops in order to avoid further international embarrassment.
A Type II error is apparent in the Iraq war that began in March 2003. As American soldiers continued to battle insurgents, even after ousting the Saddam Hussein regime, the rules became increasingly ambiguous. Those used by insurgents have one purpose: preventing a sense of security that could arise from the newly formed Iraqi government. As a result, they used tactics such as shooting at unarmed civilians, including children, and suicide bombings.