As Iran continues to dominate the foreign policy debate among Republican candidates, Former CIA Director Michael Hayden tell FOX News that he predicts Tehran will be the top threat in 2012.

FOX Chief Intelligence Correspondent Catherine Herridge reports from Washington as part of our ongoing series on national security:

Calling Iran the single greatest destabilizing force to global security, Former CIA Director Michael Hayden says the outlook for 2012 is not encouraging.

(Hayden) "The situation with Iran... in particular their nuclear program...has continued on a trajectory that gets darker with each passing day, week, and month. They seem on this inexorable arc in the direction of a nuclear capability."

Hayden says there is common ground between the Bush and Obama administrations. Both have relied on international coalition and economic sanctions, which have slowed but not stopped Iran's nuclear program.

In Washington, Catherine Herridge, FOX News Radio