In a preview of a forthcoming PBS Frontline documentary, John Rizzo, one of the top attorneys for the Central Intelligence Agency (CIA), claims that President Barack Obama has "endorsed" nearly all of the controversial Bush administration secret warfare programs.

"I was part of the transition briefings of the incoming Obama team, and they signaled fairly early on that the incoming president believed in a vigorous, aggressive, continuing counterterrorism effort," Rizzo said. "Although they never said it exactly, it was clear that the interrogation program was going away. We all knew that.

"But his people were signaling to us, I think partly to try to assure us that they weren’t going to come in and dismantle the place, that they were going to be just as tough, if not tougher, than the Bush people."

He added: "With a notable exception of the enhanced interrogation program, the incoming Obama administration changed virtually nothing with respect to existing CIA programs and operations. Things continued. Authorities were continued that were originally granted by President Bush beginning shortly after 9/11. Those were all picked up, reviewed and endorsed by the Obama administration."

This video is from PBS Frontline's documentary "Top Secret America," scheduled to air at 9 p.m. on Sept. 6, 2011.

Watch the full episode. See more FRONTLINE.