In her essay of the same name, Hannah Arendt discusses the question of public untruth in the light of the revelations provided by The Pentagon Papers. One of the points Arendt makes is that the understanding of the concept of untruth, and therefore the bar for responsibility, is different in the public realm than it is in the private sphere. Because we are dealing here not with individuals but institutions, the issue could become complicated by getting into all sorts of psychological discussions of the limits of information flow and that sort of thing. Arendt cuts the Gordian Knot by insisting that the issue is not "What did an individual know and when did he or she know it" but rather, "what institutional mechanisms were in place to ensure that the best information was available for making decisions of public import in a democratic society".
One of the biggest bombshells of the Pentagon Papers was the discovery of a discussion among RAND Corporation analysts of the possible ramifications of a North Vietnamese attack upon the US Navy in international waters. Given the knowledge of the limitations of the North Vietnamese Navy, their unwillingness to provoke a US attack directly upon them at a time most of the US military was concentrated in South Vietnam fighting the Viet Cong, and public wavering on the issue of the relevance of an Indochinese civil war for our national security, these analysts figured the attack would have to be large enough to seem clear and show hostile intent without being overly damaging (that would be impossible). With all the givens, and all the intelligence data they had, they figured out the best way to get the US behind a larger military commitment to South Vietnam was for the North Vietnamese Navy to send gunboats out and attack American ships in international waters, under the cover of darkness.
In 1964, in the Gulf of Tonkin, this is exactly what happened. Under cover of darkness, a small contingent of North Vietnamese gunboats fired upon US ships outside the territorial waters of North Vietnam. Lyndon Johnson used this clear act of aggression to push through a resolution in Congress authorizing the President to use force to protect out military and civilian assets in both North and South Vietnam.
Two problems immediately presented themselves to those who were reading the Pentagon Papers in 1971. First, the details of the events of the night were sketchy at best, sometimes contradictory, and none of the principles involved in the original attack made any further claims of North Vietnamese aggression, before or after the attack. Indeed, some of those who were named as participants - gunners and low-grade officers - insisted that nothing untoward happened that night. Furthermore, the logs of the ships were missing, so the question of the exact positions of the ships in question couldn't be verified. Were they in international waters, or were they not, provoking a North Vietnamese response? The second problem was the real bombshell. The discussions at the RAND Corporation and inside the Pentagon, which eventually ended with a discussion of the details of an alleged attack by the North Vietnamese upon American forces, occurred two years before the incident in the Gulf of Tonkin.
While most Americans understood the Pres. Johnson had lied about the success or lack thereof in Vietnam, this was evidence that it was quite probable that the roots of the deepening American commitment to South Vietnam and aggression against North Vietnam were themselves false. Whether or not the incident occurred became a moot point once it was learned that Pentagon officials were discussing such an event and how to capitalize upon it years before it actually, or allegedly, taken place.
Did Lyndon Johnson believe something happened in the Gulf of Tonkin when he sent the resolution up to Congress? Who knows? Did members of Congress, including those with access to intelligence information, believe it? Who knows? These questions are irrelevant to the larger point - the United States lied about the immediate, proximate, and sufficient cause for its deepening engagement in the South Vietnamese civil war, and the resulting conflict and social dislocation at home are laid at the feet not just of those Pentagon planners, but at Pres. Johnson and those members of Congress who voted for the Gulf of Tonkin resolution.
Does George Bush believe that Iraq hid its weapons of mass destruction so well that we still can't find them? Did he believe throughout 2002 and in to 2003 that they still had them? Who knows? More important, this question is not relevant. There is more than enough public evidence available, not just contemporaneously, but currently, that shows public officials and the institutions of our government were aware at the time various claims were made that these claims were, at best dubious, and usually out-and-out false. Whether or not any individual is morally culpable for "lying" is irrelevant.
