After the war, the Japanese chief of intelligence, Lt. General Seizo Arisue, acknowledged that his forces were never able to break the code used by the U.S. Marine Corps. (They were able to break the codes of the U.S. Army and Army Air Corps.)
Because the Navajo code talkers WERE the secret code of the Marines, they were often heavily guarded. And, according to SEC 1101 (a)(10)(B) of the Congressional Resolution honoring the code talkers with gold and silver medals:
Congress finds that...use of the Navajo Code was so successful, that...some Code Talkers were guarded by fellow marines, whose role was to kill them in case of imminent capture by the enemy.
In 1942, when the original 29 code talkers developed their "secret weapon," there were about 50,000 members of the Navajo nation. By the end of the war, 540 men had served as Marines. At least 400 of those were trained code talkers. Many had learned the 411-word vocabulary at Camp Pendleton where the secret operation was moved (from Camp Elliot) early in 1943.
For decades following the war, the Navajos’ contribution went unrecognized due to national security issues. It wasn’t until 1968 that anyone outside the military knew about the code.
The code talkers were even forbidden to tell their families about their exploits. But in July of 2001, the President and Congress of the United States honored the 29 code creators. Only five were still alive. Four went to the White House; the other was represented by his son.
The remarks of President Bush expressed the belated gratitude of a nation whose victory in the Pacific - where Allied forces were subjected to deadly kamikaze attacks late in the war - may not have been possible without the Navajos. Military commanders say the battle of Iwo Jima, for example, was won because of the code. Working around the clock, six code talkers flawlessly communicated 800 messages.
Ira Hayes, a Native American (Pima) paratrooper, was one of six Marines who raised the American flag on Iwo Jima. (He is the man on the left of the famous picture.) Soon after the photo was taken, three of the six flag raisers were dead, including Franklin Sousley who had been standing next to Hayes. Ira never understood why he survived but his buddies died.
In the rotunda of the Capitol, on 26 July 2001, the four surviving code developers received their gold Congressional Medal of Honor. In separate ceremonies around the country, approximately 300 additional code talkers received silver medals.
When the President spoke, he addressed men whose grandfathers had made the "Long Walk" to a desolate reservation just 78 years before the code talkers became Marines.