Pearl Harbor: The Seeds and Fruits of Infamy - Ludwig von Mises ...

410 Pearl Harbor: The Seeds and Fruits of Infamy
Also (3) that Washington had, therefore, had considerable preattack
intelligence about Japanese intentions. And (4) that little
of this pre-attack intelligence had been sent to Pearl Harbor.
Th e administration and top military offi cials were determined
that there be no security leaks about “Purple” and MAGIC, the
intelligence derived from it. Some of them may also have harbored
guilt about the information they had sent, or had failed to
send, our military commanders before the attack. If that was the
case, they would not have wanted it known that our decryption
of Japanese intercepts had started before the attack. Th us those
who were anxious to delay or postpone indefi nitely a hearing for
Kimmel and Short because they did not want it to be revealed
that we were decoding post-attack Japanese messages had the
support of those who wanted to conceal the fact that we had been
reading pre-attack Japanese messages.
To safeguard this major source of intelligence, Army and
Navy personnel familiar with “Purple” had been sworn to secrecy.
General Marshall himself, in his offi ce a week after the attack,
had warned his staff offi cers to go to their graves with the secret
of MAGIC. Th en in 1944, witnesses to appear before the Army
Pearl Harbor Board were again sworn “not to reveal the facts,”
i.e., the “Purple” code decrypts. 1
Similar precautions had also been taken in the Navy. Admiral
Stark testifi ed, “Anybody who was let in on that [MAGIC] had
1 An admission by a retired Army general as to the Army’s rule of secrecy was
made to the author twice, once in the presence of General Bonner Fellers and
then again in the presence of General Albert C. Wedemeyer. See also report of
Harry Elmer Barnes’ interview of Major Henry C. Clausen, January 3, 1964,
pp. 2–3 (typescript in author’s possession): “[O]aths had been taken not to
reveal the facts [the “Purple” code decrypts]. . . . Th e witnesses Miles, Marshall,
MacArthur, et al., all revealed to Clausen that they were sworn not to reveal
Purple when they were before APHB.” N.B., by March 1945, Clausen had
been promoted to lieutenant colonel.