Gregory Jacob had only been at the law firm O'Melveny & Myers for about a year when he jumped over to the U.S. Justice Department in Washington for a slot in the legal counsel's office, where an elite group of lawyers weigh and set boundaries for what federal agencies can do within the law.

Jacob arrived at Main Justice just days after the Sept. 11 terrorist attacks, and he recalled thinking that morning, as the nation was gripped in fear and anger, that he was "entrusted with a heavy responsibility, to fairly and faithfully administer the law, and to advise other federal agencies on how to do the same."