Lee Silver; Cloning Human Embryos; Evan Thomas; Bill Keller

Lee Silver, a professor of molecular biology at Princeton, responds to an announcement on the first cloned human embryo. Arthur Caplan, director at The Center for Bioethics, and Senator Sam Brownback debate the scientific and ethical ramifications of cloning. Journalist Evan Thomas talks about his Newsweek article, the most complete account of what actually happened on the United Airlines Flight 93 before it crashed. Reporter Bill Keller discusses his profile of Secretary of State Colin Powell—a key leader in the war on terror.