After opening statements from both sides, and the calling of the prosecution's first witness, the first day of the trial of I. Lewis "Scooter" Libby has ended. A few notes, based on what we saw today, on what you should be looking for as the trial moves forward.

The role of reporters. As we said in our last post, opening statements made it appear today as if testimony by the reporters whom Libby talked to, as well as some he did not, will be crucial to the case, and to determining what Libby may have said and when he said it.

Robert Novak. The defense threw a monkey wrench into the timeline of the case today by suggesting that the relevant date is not when Novak's infamous column came out, but when it was circulated by his syndicate three days earlier. Since 85 newspapers received it at that time, Libby defense attorney Ted Wells suggested, reporters from those newspapers may have known about the CIA employment of Valerie Wilson, and thus Libby may truly have learned -- or thought he learned -- about Wilson's employer from a reporter.

Memories, misty water-colored memories. Key to the defense of Libby will be the notion that human memory is simply not that reliable, especially months after the fact, which is when Libby was questioned about his memory of what had gone on at the time he was talking to reporters about Valerie Wilson. This is especially true, the defense will argue, given Libby's strenuous job, which brings us to our last point.

National security. This has been a touchy subject for all parties in the case, as rules about what can and cannot be discussed have been debated even up to and including today, when there was a contentious discussion between Wells and Judge Walton about Wells' description of what he was not allowed to say, who was constraining him and why. Libby's team will try to argue that Valerie Wilson was simply not important in the context of all that Libby had to worry about, which included, according to Wells' opening statement, potential assassination attempts against President Bush and attempts by al-Qaida to acquire nuclear devices and anthrax and bring them to the United States. (It should be noted that none of these threats has been corroborated, at least in court; they were simply discussed as issues that had been brought before Libby at the time he was dealing with reporters on the Wilson issue.)