Treason against the United States, shall consist only in levying War against them, or in adhering to their Enemies, giving them Aid and Comfort. No Person shall be convicted of Treason unless, on the testimony of two Witnesses to the same overt Act, or on Confession in open court.
Although this is a very restrictive standard for conviction, Hasan fits it perfectly. His act of murdering 13 people in public in front of many witnesses while yelling, "Allah Akbar!" was definitely an act of war against the U.S. and was witnessed by more than enough people to fulfill the constitutional standard. Add to that his repeated pro-Jihadi rants in front of large audiences that constituted both: 1) giving aid and comfort to our Islamist enemies and 2) compelling evidence of anti-American animosity that would establish he intended to wage war against the U.S. by the mass murders he committed, and you have a slam dunk treason case that could have been tried and won within a few months after the actual crime.
Indeed the present, fictitious "workplace shooting" rationale being offered by the Administration is dangerously weak and might expose it to an insanity defense. Worst of all, it ignores Hasan's treasonous motive. That leaves the prosecution touting a fictitious explanation for his conduct in the form of some kind of adverse personal interactions that led him to "snap." It's not likely to work. The defense will be able to jump on that pile of B.S. like a tarantula on a bug and use it to show Hasan had no sane, but evil, reason for his acts, thereby opening a huge door for an insanity defense.
That being the case, the compelling question is, "Why didn't Obama authorize such a totally appropriate, easily winnable treason prosecution?" The only logical answer is he is a traitor who's determined to give as much "Aid and Comfort" to our Islamist enemies as he possibly can.