MARGARET WARNER: The court-martial of the Army psychiatrist who opened fire on scores of fellow soldiers in 2009 got under way today at Fort Hood in Texas.

Major Nidal Hasan is charged with many counts of murder and attempted murder for the attack that killed 13 people and wounded more than 30. In an opening statement, the prosecutor said Hasan had tried to kill as many soldiers as he could.

In his opening statement, Hasan, who is representing himself, said, "The evidence will clearly show that I am the shooter."

Los Angeles Times reporter Molly Hennessy-Fiske is covering the trial and joins us now from Fort Hood.

Molly, welcome.

Let's start with that, the most dramatic moment of today, which is Colonel Hasan admitting he was the shooter.What was that moment like?What else did he have to say?

Los Angeles Times: Well, there were a lot of open questions going into these opening statements.

It wasn't clear, since Major Hasan, as you mentioned, is representing himself, what he was going to say, whether he was going to use opening statements as an opportunity to make a statement and go beyond acting as his own attorney. But he kept it brief. He only spoke for several minutes.

He did talk about the facts pointing to him being the shooter. He made some other statements about his allegiances on having been in the Army, but switching sides, and then talked about viewing himself as a mujahideen, but was very brief. And then later on in the day, we saw several witnesses speak, but Major Hasan declined to take the opportunity to cross-examine largely.

There were some instances where he did, but, again, that was fairly brief.

MARGARET WARNER: Now, he was responding, of course, to the opening statement by the military prosecutor. What kind of a case did that prosecutor lay out against him?

MOLLY HENNESSY-FISKE: Well, the prosecutor talked -- one of the prosecutors talked in opening statements about wanting to prove not only that Major Hasan committed the shooting, but also his motive, that these shootings -- the charges, premeditated murder and attempted premeditated murder, that it was premeditated, that he had motive.

And so some of the witnesses that we saw earlier in the day had to do with that, the individual who the prosecutors were saying had sold the weapons, the guns to Major Hasan, a gentleman from the shooting range where he apparently had practiced target shooting with silhouettes in -- the silhouette shapes instead of target shapes, and then some individual who had known him from his apartment complex and also from the mosque that he attended here in Killeen.

MARGARET WARNER: Now, if Major Hasan is admitting he was the shooter, why was there -- why didn't he just plead guilty or negotiate an agreement there?

MOLLY HENNESSY-FISKE: Well, in military court in capital cases, like this one, where he is facing the potential, if convicted, of facing the death penalty, he's not allowed to plead guilty.

He had also tried to mount a different kind of defense once he took over as his own attorney and argue -- it's called the defense-of-others defense, where he was arguing that he had done the shooting, but that he had done it in order to protect individuals overseas. He targeted -- he said he targeted soldiers who were preparing to deploy because he wanted to protect members of the Taliban, who he saw as sort of allies.

But the judge thus far has rejected that defense, so it's sort of unclear what defense he's going to pursue, what defense strategy.

MARGARET WARNER: And then how did it come about that he is representing himself?

MOLLY HENNESSY-FISKE: Well, he had had a civilian lawyer in the beginning. And he had fired his civilian lawyer. Then he had military lawyers, and he had requested to represent himself in recent months. And the judge allowed that.

He had not initially wanted his military lawyers to stay on, but the judge had asked that they stay on as standby counselor or military legal advisers. So those lawyers are there. Two of them sit at the defense table with Major Hasan and a third sits in the gallery.

And they are there to sort of offer him advice on military law. And there was one point today where he sort of paused to consult with them on a particular matter.

MARGARET WARNER: And was there a determination made about his mental competence to serve as his own lawyer, I guess, to stand trial?

MOLLY HENNESSY-FISKE: There was. That happened early on.

And there was also a sort of secondary evaluation done where they took into consideration his physical status in terms of being able, physically able to represent himself, because he is -- he's in a wheelchair. He was shot during the attack and is paralyzed from the chest down. That was a consideration. But he insisted that he was strong enough to do it, that he could take breaks, but is OK with sitting for long periods of time that it's going to require for this trial, because the judge has already estimated that it's probably going to take at least a month and possibly several months

MARGARET WARNER: And, finally, of course, this is a military trial, not a civilian criminal trial. What difference does that make in the way the trial is conducted, the rules of evidence and, of course, the jury?

MOLLY HENNESSY-FISKE: Well, there's a lot of differences.

You have a jury that is made up of 13 individuals who are of Major Hasan's rank or higher. So you have a major, similar to Major Hasan, but then you also have a colonel -- three colonels and nine lieutenant-colonels, which is a high-ranking crowd. These are elite individuals who have served in command posts. I think 11 of them, 11 of the 13 have served in command. A number of them have served overseas in Afghanistan and Iraq.

These are, you know, skilled individuals with a lot of, you know, burnished records. One of them, at least one of them attended West Point. A lot of them have advanced degrees. And in terms of a verdict, they have to have a unanimous verdict in order to have a death sentence.

And if they -- what happens is they make a vote by secret ballot on what their verdict is going to be. And if they can't achieve a two-thirds majority, then they end up quitting. So it's significantly different from a civilian trial.

MARGARET WARNER: Well, Molly Hennessy-Fiske of the Los Angeles Times, thank you.