In This War with no Front Lines on a Map, never Was Intelligence More Essential - but Seldom Has Intelligence Performed so Poorly

"In this war with no front lines on a map, never was intelligence more essential - but seldom has intelligence performed so poorly." Discuss in regard to Vietnam, 1962-72.
Even though the US had some of the finest intelligence services in the world, the disaster at Pearl Harbour on Sunday 7 December 1941 took the Americans completely by surprise even though they were listening to Japan's most secret radio traffic and there were many signs that such attack was possible. But the problem was that the US intelligence services did not read the signs as they should have and this amounted to a…