FBI Director James Comey says he encourages all agents and analysts to visit the Holocaust Museum in Washington because “we want them to see, in a gut-wrenching, nauseating way, what the abuse of power on an almost unimaginable scale looks and feels like, because we’re about to give them extraordinary power.”

“And then there’s a second reason that is I want them to see what we are capable of,” Comey told CNN’s Wolf Blizter at the Aspen Security Forum. “I want them to understand what human beings are capable of, that we are — one of our greatest strengths is our ability to convince ourselves of the righteousness of our own cause. And one of our greatest weaknesses is our capacity to surrender our moral authority to the group, so it can be hijacked by the least common denominator.”

“I want them to stare at that and understand the weaknesses that we all share, because they are about to have tremendous power and I want them to have sense of that in a way that will last them their whole career.”

Much of the conversation at the forum was about ISIS, which Comey now considers a bigger threat to the homeland than al-Qaeda.

“They have adopted a model that takes advantage of social media in a way to crowd-source terrorism. They have invested about the last year in pushing a message of poison, primarily through Twitter, but other parts of social media, that is a siren song with two dimensions,” Comey said.

“They are preaching through social media to troubled souls, urging them to join their so-called caliphate in Syria and Iraq, or if you can’t join, kill where you are. And Twitter is a valuable enterprise, because it works to sell shoes or to sell ideas. It works to sell this message to troubled souls.”

The director added that ISIS makes their terrorists more available to speak to potential recruits and are “trying to reach are people that al-Qaeda would never use as an operative.”

Comey said “dozens” of Americans are now fighting for ISIS, but they’re a “hard phenomenon” to track “because they range in age from 18 to 62.”

He said the FBI is “not in a position to say” yet if Chattanooga shooter Mohammed Yousef Abdulazeez was ISIS or AQAP.

“We’re still combing through his entire life, including his electronic media, to understand, so, who was he communicating with and about what?” Comey said. Part of that is “to understand so what happened in Jordan, who influenced him, who did he meet, what did he consume, that sort of thing.”