Republican presidential candidate Dr. Ben Carson doubled down on his previous language this morning, saying that al Qaeda was not an existential threat to the United States in 2001 and 2003. Today, he told ABC News that ISIS is more of a threat now than al Qaeda was in 2001 and 2003. "They weren’t nearly as developed as they are now -- at that point,†Carson said in response to an ABC News question. "That was my point. This is so much greater a threat than that was.†Carson also said the attacks on the World Trade Center in 2001...