Arguably, no agency has changed more in the years since the Sept. 11, 2001, attacks than the C.I.A., and no agency could be affected more by the new direction of the secret wars laid out by American officials on Thursday.

More than half of the C.I.A.’s work force joined the agency after 2001, and many of those new officers have spent the years since almost exclusively on the work of man-hunting and killing.

Some American officials and outside experts believe it could take years for a spy agency that has evolved into a paramilitary service to rebalance its activities.

“There’s a huge cultural and generational issue at stake here,” said Mark Lowenthal, a former senior C.I.A. official. “A lot of the people hired since 9/11 have done nothing but tactical work for the past 12 years,” he said, “and intellectually it’s very difficult to go from a tactical approach to seeing things more strategically.”