Hired in 2001 by the National Security Agency to help it catch up with the e-mail and cellphone revolution, Thomas A. Drake became convinced that the government's eavesdroppers were squandering hundreds of millions of dollars on failed programs. He contacted a reporter for The Baltimore Sun. Today, because of that decision, Mr. Drake, 53, ... faces years in prison on 10 felony charges involving the mishandling of classified information and obstruction of justice. The indictment of Mr. Drake was the latest evidence that the Obama administration is proving more aggressive than the Bush administration in seeking to punish unauthorized leaks. In 17 months in office, President Obama has already outdone every previous president in pursuing leak prosecutions. His administration has taken actions that might have provoked sharp political criticism for his predecessor, George W. Bush. Mr. Drake was charged in April; in May, an F.B.I. translator was sentenced to 20 months in prison for providing classified documents to a blogger; this week, the Pentagon confirmed the arrest of a 22-year-old Army intelligence analyst suspected of passing a classified video of an American military helicopter shooting Baghdad civilians to the Web site Wikileaks.org.