Communication...  

Communication is the foundation for sharing information between people to ensure that everything is understood and can be acted upon. Without good communication, missions fail and others can not help to fulfill the mission. Another reason communication is important is because you leave others out of the loop and they can not inform higher the proper status of what is going on. Communication as defined in the American Heritage Dictionary is the exchange of thoughts, expressions, and or information. This is the basis of all communications. 
Communication among individuals, teams, units, and organizations is essential to efficient and effective mission accomplishment. Two-way communication is much more effective than one-way communication. Mission accomplishment depends on information passing accurately to and from subordinates and leaders, up and down the chain of command and NCO support channel, and laterally among adjacent organizations. 

The Army has only one chain of command. Through this chain of command, leaders issue orders and instructions and convey policies. A healthy chain of command is a two way communications channel. Its members do more than transmit orders; they carry information from within the unit or organization back up to its leaders. They furnish information about how things are developing, notify the leader of problems, and provide requests for clarification and help. Leaders at all levels use the chain of command to keep their people informed and render assistance. They continually facilitate the process of gaining the necessary clarification and solving problems.
The downfall of communication can lead to mission failure and this can not be the case when the mission of any kind fails due to poor communication.