Lawyers for Army Private Ask Judge to Acquit Him of Aiding Enemy FORT MEADE, Md. - Defense lawyers for Pfc. Bradley Manning asked a military judge on Monday to acquit him of the most serious charge he faces, that of aiding the enemy by providing classified information to WikiLeaks, as they began to present their witnesses at his court-martial. Private Manning's lead lawyer, David Coombs, filed four motions asking the judge, Col. Denise Lind, to find him not guilty of many of the charges on the grounds that prosecutors had failed to prove them in their five-week presentation of the case. She did not immediately rule on the matter, and she asked for a response from the government by Thursday. Early in the day, the defense showed the now-familiar video footage from a helicopter gunship in Iraq as it fired on people on the ground who turned out to include two Reuters journalists, who were killed. The news agency unsuccessfully sought access to video and other records of the shooting until Private Manning provided it to WikiLeaks, which edited it and posted it on the Web under the title "Collateral Murder." The first defense witness, Chief Warrant Officer 2 Joshua Ehresman, who worked with Private Manning in Iraq, described relatively relaxed computer security rules that permitted soldiers to download classified information onto CDs, in part because their regular computers crashed on a regular basis. He said analysts were permitted to play music and watch movies that were stored on the shared hard drive they used for their work. The charges against Private Manning, who has said he downloaded classified files he wanted to leak onto CDs he labeled as Lady Gaga songs, include violating security rules governing the classified computer system. The prosecution rested its case against Private Manning last week after trying to prove officially what the soldier has already admitted - that he provided 700,000 confidential military and diplomatic documents to WikiLeaks. But prosecutors also sought to prove the charge of aiding the enemy, which Private Manning had not admitted, by showing that documents he leaked were posted online and later downloaded by aides to Osama bin Laden and given to the Qaeda leader. Private Manning has already pleaded guilty to crimes that could send him to a military prison for up to 20 years. But he could be sentenced to a life term if convicted of aiding the enemy. Some advocates of government openness view that possibility as a dangerous precedent, since it would mean that any classified information posted online could be viewed as helping the enemy, assuming that the enemy has Web access, regardless of the intent of the person posting it. The defense team on Monday listed the first 10 witnesses it intends to call. In addition to Private Manning's fellow soldiers in Iraq, they include a woman, Lauren McNamara, who is expected to discuss her online conversations with him; the retired former chief prosecutor at Guantánamo Bay, Col. Morris D. Davis, who may speak about the "detainee assessments" from Guantánamo that were among the documents Private Manning disclosed; and Yochai Benkler, a Harvard law professor who has written about WikiLeaks. The trial is unfolding against the backdrop of the dramatic story of another leaker, Edward J. Snowden, the former National Security Agency contractor who shared thousands of classified documents about American and British surveillance programs to The Guardian and other publications. Far from being deterred by the prosecution of Private Manning, Mr. Snowden has cited the soldier as an inspiration for his own decision to expose what he considered to be government wrongdoing. The emergence of Mr. Snowden, who is reported to be in the transit area of Moscow's international airport while he seeks asylum in multiple countries, conceivably could hurt Private Manning's case for a shorter sentence. Government officials may suggest that only a lengthy prison term can discourage others from making secrets public, though that strategy failed in the case of Mr. Snowden.