FORT MEADE, Maryland (Reuters) - The military judge hearing the court-martial of the U.S. soldier accused of the biggest leak of classified material in the nation’s history refused on Thursday to dismiss the most severe charge the defendant faces, aiding the enemy.

U.S. Army Private First Class Bradley Manning (C) is escorted out after a day of testimony at his court martial trial at Fort Meade, Maryland, July 8, 2013. REUTERS/Jonathan Ernst

That is one of 21 counts that U.S. Army Private First Class Bradley Manning is charged with, but it carries the possibility of life in prison.

“He was knowingly providing intelligence to the enemy,” said Judge Colonel Denise Lind in rejecting a motion by Manning’s lawyer to dismiss that charge.

Lind said military intelligence analysts such as Manning were trained to assume that anything posted on the Internet could be accessed by the enemy.

Manning, 25, is charged with sharing more than 700,000 classified files, combat videos and State Department cables with the anti-secrecy website WikiLeaks while serving as a low-level intelligence analyst in Iraq in 2009 and 2010.

The case stands as a test of the limits of secrecy in the Internet era. Manning’s lawyers have sought to portray him as naive but well-meaning, intending to provoke debate by providing Americans with more information about the wars in Afghanistan and Iraq.

He acted through the WikiLeaks site, founded by activist Julian Assange, who has drawn the anger of the U.S. government, which charged that the leaks put national security and intelligence operatives at risk.

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.

Snowden has been holed up in the transit area of Moscow’s Sheremetyevo airport, seeking a country to offer him asylum.

NEGLIGENCE, NOT ILL INTENT

Defense lawyer David Coombs earlier this week had argued that Manning was guilty of negligence but not the “general evil intent” standard required to justify the heavy charge.

Coombs also argued that the government was overreaching by charging his client with stealing information from a government database.

“The government is trying to say that the word database encapsulates everything under the sun,” Coombs said. “Words matter.”

Over the course of the trial, defense lawyers have sought to show that the slightly built Manning was naive but well-intentioned in seeking to inform Americans about the reality of the wars in Afghanistan and Iraq.

The trial will also hear from prosecution witnesses in a rebuttal phase following the close of the defense phase last week.

A top U.S. defense official told a security forum in Aspen, Colorado, on Thursday that the government is overhauling the way it stores information to prevent leaks similar to those orchestrated by Snowden or Manning.

Snowden has provided documents about secret U.S. and British eavesdropping programs to Britain’s Guardian newspaper, the German magazine Der Spiegel and the Washington Post. He also made allegations about U.S. eavesdropping on Chinese targets to the Hong Kong-based South China Morning Post.