CBS News: In an interview with ABC's "Good Morning America," U.S. Attorney General Eric Holder spoke of the ongoing fight to protect American national security and expressed his growing concern with the threat of homegrown terror - a danger which he said "keeps me up at night." "What I am trying to do in this interview is to make people aware of the fact that the threat is real, the threat is different, the threat is constant," Holder told ABC's Pierre Thomas, in an interview that aired Tuesday morning.