Despite openness pledge, President Obama pursues leakers

``The Obama administration, which famously pledged to be the most transparent in American history, is pursuing an unexpectedly aggressive legal offensive against federal workers who leak secret information to expose wrongdoing, highlight national security threats or pursue a personal agenda. In just over two years since President Barack Obama took office, prosecutors have filed criminal charges in five separate cases involving unauthorized distribution of classified national security information to the media. And the government is now mulling what would be the most high-profile case of them all - prosecuting WikiLeaks founder Julian Assange. ''