Supporters of Army Pfc. Bradley Manning gathered outside Fort Meade in Maryland this weekend to protest the Wikileaks leaker’s imprisonment.

Nearly 2,000 people rallied Saturday to support the whistleblower, according to a news release. Speakers at the event included Daniel Ellsberg, the military analyst who leaked the Pentagon Papers, and former Army lieutenant Dan Choi, a strong opponent of the “Don’t Ask, Don’t Tell” policy.

Manning’s trial began today three years after he was arrested in Iraq. The 25-year-old has already pleaded guilty to charges related to leaking classified documents that may send him to prison for up to 20 years. But he’s also been charged with aiding the enemy, which carries a term of life imprisonment. Prosecutors said Manning knew the documents he leaked would aide the enemy and did it to “gain the notoriety he craved.” Manning denies this charge.