The military judge in Manning's court martial, Col. Denise Lind, said she will announce her verdict Tuesday. Closing arguments in the military bench trial concluded Friday after which Lind began her deliberations.
Protesters rallied Monday in several German cities, London, Brussels and Perth, Australia, and Washington in support of an acquittal.
Manning has admitted culling and leaking some 700,000 classified defense and diplomatic documents containing embarrassing -- some argue criminal -- evidence of American conduct abroad. Among the most potent information were videos of U.S. aircraft launching missiles that hit unintended targets and diplomatic cables that revealed indifference or contempt for allies' interests.
While Manning's supporters call him a heroic whistleblower, those in the top levels of the U.S. government have made no bones about their contempt for Manning's allegedly treasonous actions. Vice President Joe Biden called Manning a "high-tech terrorist."
Manning's defense team has sought to portray him as a troubled, naive soldier who struggled to fit in because he was gay serving under the military's "don't ask, don't tell" policy. One of Manning's lawyers called his client a socially conscious soldier and a "guy who cared about human life," CBS News reported Monday.
Prosecutors have described Manning, 25, as precisely the opposite -- a "glory-seeking traitor" whose desire to be thought of as a hero led him to betray his country.
"This is a case about a soldier who systematically harvested hundreds of thousands of documents from classified databases and then dumped that information onto the Internet into the hands of the enemy," prosecutor Capt. Joe Morrow said during the trial. He said Manning demonstrated a sense of "arrogance" in releasing the information.
One of the central questions Lind must answer is whether Manning knew or should have known the information he was passing on to WikiLeaks would eventually make its way to terrorists, particularly al Qaida, and enhance their operational capabilities.
Manning already admitted his guilt to a majority of the charges against him and faces 20 years in prison. He faces life in prison for charges of aiding the enemy, espionage, computer fraud and federal theft.
Manning's time in military custody has already been the subject of intense debate. Lind ruled in Manning's favor, saying the conditions under which he was held in a military brig in Quantico, Va., were unduly harsh. Calling him a suicide threat, Manning was held in solitary confinement for 23 hours a day. Sometimes he was stripped naked so, guards said, he couldn't use his clothing to hang himself. Manning denied he was a suicidal and Lind said whatever sentence he receives, 112 days will be shaved off due to his treatment at the facility.
Among Manning's most prominent supporters is WikiLeaks founder Julian Assange. Himself a target of scorn by high-level government officials, the enigmatic Assange said Friday Manning's conviction would be "the end of national security journalism in the United States," RT news agency reported.
Other supporters hailed Manning's decision to publish the information.
"It's time we reclaim the word 'patriot.' The kind of patriot we need today is not someone who defends all of our country's history and actions, it's someone willing to stand up for our country's future, taking risks to ensure it's a just one," campaign organizer Emma Cape from the Bradley Manning Support Network said in a speech at Fort McNair in Washington.
The Washington protest coincided with worldwide protests that, though sparsely attended, were intended to demonstrate the international support for open government and fewer state secrets. Manning's treatment and the decision by military prosecutors and government officials to aggressively prosecute him has become a focal point in the movement, RT reported.