(New throughout with legal expert views and case details)
By Medina Roshan
July 29 (Reuters) - The verdict will be read on Tuesday at the court-martial of the soldier accused of the biggest leak of classified information in U.S. history, the judge said, with the biggest question whether he will be convicted of the most serious charge of aiding the enemy, carrying a life sentence.
Legal observers said it was highly likely that Army Private First Class Bradley Manning, who in March pleaded guilty to lesser charges related to sharing some 700,000 documents with the WikiLeaks anti-secrecy website in 2010, will be found guilty on at least some of the 21 criminal counts.
"The difficult part is did he know that the information was going to Al-Qaeda and the Taliban? To me, that is the linchpin of the case," said Richard Rosen, a professor of law at the Texas Tech University School of Law and a former military lawyer. "If he's not found guilty of that charge, the punishment is going to be a lot less severe in my opinion."
Judge Colonel Denise Lind said on Monday that she plans to issue her verdict in the case at 1 p.m. EDT (1700 GMT) on Tuesday in Fort Meade, Maryland.
Manning, originally from Crescent, Oklahoma, opted to have his case heard by Lind, rather than a panel of military jurors.
Military prosecutors have called the 25-year-old defendant a "traitor" for publicly posting information that the U.S. government said could jeopardize national security and intelligence operations.
Lawyers for the low-level intelligence analyst said Manning was well-intentioned but naive, hoping that his disclosures would provoke a more intense debate in the United States about diplomatic and military actions in Iraq and Afghanistan.
More than three years after Manning's arrest in May 2010, the U.S. intelligence community is reeling again from leaked secrets, this time exposed by former intelligence contractor Edward Snowden, who has been holed up in the transit area of a Moscow airport for more than a month despite U.S. calls for Russian authorities to turn him over.
WikiLeaks founder Julian Assange has surfaced again as a major player in the newest scandal, this time aiding Snowden in eluding authorities to seek asylum abroad.
The cases of Manning and Snowden, a former contractor for a U.S. spy agency, illustrate the difficulties of keeping secrets at a time the internet makes them very easy to share widely and quickly. In addition, more people are granted access to classified data.
"The bar has become very low for what the government has to prove in order to convict someone for disclosing classified information to the media," said Elizabeth Goitein, a security specialist at New York University's Brennan Center for Justice.
She said that military courts had made it easier to convict people on charges of aiding the enemy.
"There has been a heightened standard of intent that has been required," Goitein said. "We're really starting to see the court chip away at this." (Writing by Scott Malone; Editing by Barbara Goldberg, Steve Orlofsky and Grant McCool)