As Obama's top counter-terrorism advisor, Brennan also insisted the administration will continue working to close Guantanamo Bay where more than 90 Yemenis with links to terrorism are still being held.
"We try to adapt the tools in the right way," Brennan said on CNN's State of the Union. "We are also a country of laws. This was an individual who was arrested on U.S. soil. If we decide at some point that we're going to charge and hold somebody under the enemy combatant status, it's a tool that is available to us. We made a decision to do this. "
"We have great confidence in the FBI and other individuals in terms of debriefing. We have great confidence in our court system so that we can use that to our advantage," he said. "And individuals in the past have, in fact, given us very valuable information as they've gone through the plea agreement process."