Early in 1942, Johnston met with Major General Clayton B. Vogel, the commanding general of Amphibious Corps, Pacific Fleet, and his staff. Johnston staged tests under simulated combat conditions which demonstrated that Navajo men could encode, transmit, and decode a three-line English message in 20 seconds, versus the 30 minutes required by machines at that time. The idea was accepted and Vogel recommended that the Marines recruit 200 Navajo.