With the words "This is London," Edward R. Murrow's groundbreaking radio broadcasts from 1939 to 1941 brought the blitz into America's living rooms. Countering the tide of U.S. isolationism, Murrow told his huge audience that the United States could not avoid a confrontation with Hitler and that the bombs it heard falling during his reports would eventually be targeted at American cities. But although often cited as the paragon of journalistic objectivity,...