You might think that what you know is simple to define - that is, the information that you are able to recall from memory or experience, or something to that effect.
Of course, as with so many things, the legal definition of "knowledge" differs from what one might consider a more conventional definition.
Legally speaking, there are different types of "knowledge." There's "Actual knowledge" which is what you know directly and clearly. There's "Personal Knowledge," which is knowleedge gained through firsthand observation or experience (as opposed to beliefs based on what others have said). There's imputed knowledge, such as the presumption that the agency is aware of the dealings of its agents.
There are other types of knowledge, but what I want to focus on is Constructive Knowledge. Constructive knowledge is the type of knowledge that one using reasonable care or diligence should have, and therefore is attributed by law to a given person. Basically, what this means is that it's stuff that you "should have known," that the law determines you are responsible for, even if you don't know. One example of this would be warnings. Every year, several letters are sent out by pharmaceutical companies to doctors all over the country. These letters contain warnings that certain medications have been linked to some side effect that was not listed in the Physician's Desk Reference, or that was unknown when the FDA granted approval. This letter, known by some as a "dear doctor" letter, serves to give these doctors constructive knowledge of the side effects, in theory.
Why do I waste so many words to mention this? Because this concept of constructive knowledge, or "should have known," has applications all over. An enlisted person cannot avoid liability for violating the UCMJ or a military or base regulation simply because he or she didn't "know" about it - they should have known. If you are driving in a town you've never been to and see a purple traffic light, the purpose of that color is described in the town, and you are presumed to know what it means.
The same should hold true for our military. When military lawyers warn the Pentagon that interrogation techniques they are looking into may be illegal, then the DOD should know that they need to tread carefully, and to look into the legality of the issue, rather than dive in with reckless disregard for the law. This knowledge should also be imputed to the leadership of the DOD, such as the Secretary of Defense, the President, and others. It's no wonder Senator Lindsay Graham (R-S.C.) referred to this situation as follows: "The guidance (administration lawyers) provided will go down in history as some of the most irresponsible and shortsighted legal analysis ever provided to our nation's military and intelligence communities." We're talking about liberty, and sacrificing oversight concerning legality and individuals' liberties because there is a "high degree of urgency," as Pentagon office of general Counsel William "Jim" Hayes stated is wrong, particularly in light of his trite explanation that he was unaware of the concerns over legality (see "knowledge" - above).
Someone should have to answer for this, and heads should have to roll.