What is the key order that should be issued immediately after receiving directives from a superior?

The key order that should be issued immediately after receiving directives from a superior is a WARNORD, which stands for Warning Order. A Warning Order provides preliminary information and outlines what is to follow in terms of specific plans or operations. It is crucial for allowing subordinate units to prepare and start planning for an upcoming operation or task.

A WARNORD enables leaders to communicate the intent of the superior and necessary information quickly, allowing time for units to gather and organize necessary resources and personnel. This step is essential because it sets the stage for the subsequent detailed planning processes, such as the development of an Operations Order (OPORD) or a Fragmentary Order (FRAGORD).

In contrast, BAMCIS is a mnemonic used for troop leading procedures, OPORD is a formal plan, and FRAGORD is an update to an existing order. Each of these has its specific context and timing for issuance, but the immediate response to receive directives effectively and begin preparation is encapsulated in the Warning Order.