The Obama administration is facing criticism for prosecutions brought under the US Espionage Act against government employees accused of leaking sensitive information. Mark Feldstein, professor of media at the University of Maryland, sees a worrying trend of espionage prosecutions since President Obama took office. To everyone's surprise, the Obama administration has escalated the war against whistleblowers and the attacks on information that journalists and the public were depending on to get evidence of wrongdoing by powerful institutions and individuals," Prof Feldstein says. On Friday, Thomas Drake, a former senior official at the National Security Agency, a highly secretive US spy agency, was sentenced to one year's probation, after the Department of Justice's case against him collapsed. He had been accused of passing on information to a journalist about a government computer programme he considered wasteful. Outside court, Mr Drake said the government's prosecution had been "vindictive and malicious". According his lawyer Jesselyn Radack, the charge that he passed on secret information was a ''bald-faced lie''. Critics say the US classification system is often arbitrary, with documents often stamped ''classified'' when the content is not secret or that sensitive.