Who is the real Bradley Manning: a fragile and unstable being, with suicidal tendencies, or a man of conscience, aware of his actions and determined to make his mark in the world?

In 11 days of pre-trial hearings that ended Tuesday, defense attorneys and prosecutors drew competing portrayals of the US soldier at the center of the most massive leak ever of classified US documents.

Small of frame and frail-looking, with closely-cropped blond hair and a bespectacled boyish face, Manning does not look like one of the most celebrated "whistleblowers" in US history.

But this former army intelligence analyst is accused of downloading and then sending thousands of US military documents related to the wars in Iraq and Afghanistan and another 250,000 US diplomatic cables to the anti-secrecy website WikiLeaks between November 2009 and May 2010.

The leak, staggering in size and scope, set off a global diplomatic storm and provoked the fury of the world's most powerful country.

It's been a heavy load for the 24-year-old, who joined the army more out of family pressure than personal commitment. He was arrested in May 2010 in Iraq and incarcerated under "maximum security" conditions.

Testimony by government witnesses before a military court at Fort Meade, Maryland casts him in stark terms: "depression," "anxiety," "panic attacks," prone to "unpredictable behavior."

They also spoke of his "lack of communication," sleepwalking and his struggle over his sexual identity.

Prison personnel at the US Marine Corps base at Quantico, Virginia, where Manning was held from July 2010 to April 2011, even cited episodes in which the soldier allegedly licked the bars of his cell in his sleep, wept while covering his head with his hands, and grimaced at the sight of himself in the mirror.

The prisoner's behavior, they said, justified keeping him under a super-strict suicide watch for nine months.

"To make a difference in the world"

The defense, on the other hand, charged that Manning was a victim of judicial persecution. He was not suicidal and the near-total isolation to which he was subjected amounted to "unlawful pre-trial punishment," his lawyers argued, calling for the case against their client to be dismissed.

Psychiatrists agreed that the strict detention regime was unjustified, and that Manning did not exhibit suicidal behavior.

"Bradley is probably one of the most intelligent people I've ever met. He's young, though, and has not a lot of experience. But he does a lot of things from the heart. He cares about people, his actions are driven by that," his lawyer, David Coombs, said earlier this month.

According to Coombs, Manning's dream is "to go to college, he wants to go into public service, join some sort of campaign groups, and one day maybe run for office."

"He wants to make a difference in this world," he said, adding, "But he has already made a difference."

From those two conflicting portrayals, it is difficult to discern Manning's real personality.

The soldier seems far from defeated. At the pre-trial hearings at Fort Meade, which resume January 8, he diligently follows the debates, leafing through documents, taking notes, with little show of emotion.

Late last month, when he testified for the first time, he struck a confident and thoughtful tone as he told the court of the conditions of his confinement, punctuating his account with flashes of humor and theatrical gestures.

While admitting that he had contemplated suicide "several times," going so far as to turn a bedsheet into a noose early in his incarceration, Manning said he never gave up on life.

At no point in the hearings did he express regret for his actions.

Nathan Fuller, spokesman for Manning's support group, stressed his idealistic motives in leaking the US documents: to generate debate and allow people to see what their government was doing behind their back.

Currently imprisoned at Fort Leavenworth, Kansas, Manning could be sentenced to life in prison if convicted of "aiding the enemy."

The trial proper is expected to begin in March.