spartans_in_darkness

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the performance of the SIGINT community in
reporting the approach of the Tet offensive.
Surprisingly, many of the sources quoted earlier
themselves contain conditional oualifiers to their
praise of SIGINT.I
L...-_---', A history of U.S. intelligence prior to Tet
added this interesting point about SIGINT's role:
It appears, however, that U.S. analysts did fall
victim to the "Ultra" syndrome, the tendency to
rel. on sources of information that han' a reputation
for accurate and timely information. In
early 196H. SIGINT revealed the movement of
:-1YA units as they massed along the DMZ ...
especially near Khe Sanh. In contrast, VC units
that were surrounding and infiltrating southern
cities remained relatively quiet ... as U.S. intclligence
agencies became mesmerized bv the
electronic image ... they tended to downplay
... reports that indicated a VC attack against
the cities of the sOllth. 12
(8//8I:) Obviously, such different opimons,
even within the same documents and monographs,
suggest that, despite the confident pronouncements
of some NSA high officials, there
remains much controversy about SIGINT's role
prior to Tet. Some of this may derive from the
imprecision of the claims, Exactly what is meant
by "predict" A dictionary definition states simply
that it means to "foretell in advance." Yet, how
much needs to be foretold to be effective, especially
in a military context Is merely saying
1
"something" may happen sufficient Do the commanders
of armies need more to act upon' Or
does the word "predict" accurately portray the
SIGINTpr()cessprior to Tet Could another term
describe what SIGINT actually was attempting to
do and, at the same time, allow for a precise evaluation
of its performance.
(8//8f) In order to arrive at some determination
of SIGINT's role and its effectiveness prior to
the attacks, we need to understand the complex
and numerous factors that influenced how
American officiaIs'received'irifelligerice'ft6ffi'SIG:::
INT sources. So in the ensuing narrative, we will
try to answer the following questions: What was
the military situation in early 1968 How did SIG­
INT fare in a battlefield support role How did
both sides perceive their respective positions visa-vis
the other in 1968 'Whatwere the aims of the
North Vietnamese during the Tet offensive
Exactly what did SIGINT observe of the North
Vietnamese and Viet Cong preparations for the
offensive 'What was the effect of the siege of Khe
Sanh on American military intelligence' How was
this intelligence disseminated and to whom How
was it received And what effect did it have'
(S//SI) In reviewing the chronology leading
up to Tet, we will be concerned primarily with
SIGINT's role prior to the attack. This is important,
since the reporting by SIGINT before 31
January is what the various customers in
Washington and Saigon used to make their
assessments of the situation, as well as their subsequent
preparations (or inaction). Although we
will consider the post-Tet assessments and evaluations,
these documents, by their very nature,
tend to correlate post-event understanding with a
search for "indicators" that were reported earlier.
This tendency distorts our understanding of what
happened prior to Tet. By emphasizing a handful
of details that "predicted" Tet, as these evaluations
did, the rest of the background "noise," that
is, other intelligence, influences, biases, all of
which shaped the American attitude prior to the
offensive, were ignored, or down played in signif-
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