The judge rejected requests to drop 10 of the 22 charges including “aiding the enemy” against the 24-year-old, saying that his trial, scheduled for September, will most likely be delayed by two months.
The decision was announced during a pre-trial hearing before Manning’s court martial.
The former US army intelligent analyst was arrested in May 2010 for allegedly giving more than 700,000 military field reports from Iraq and Afghanistan and US diplomatic cables to Whistleblower website WikiLeaks.
Now the defense is arguing that the language used to charge Manning is unconstitutionally vague.
The leak of the military documents shed light on untold civilian killings, while the diplomatic cables sparked a firestorm by disclosing the private remarks of heads of state and candid observations by senior US officials.