Final answer:
Edward Murrow defended Milo Radulovich to challenge the tactics of McCarthy and the anti-Communist hysteria, and to send a message that dissent should not be equated with treachery.
Step-by-step explanation:
Edward Murrow defended Milo Radulovich because he believed in the tactics of misdirection and guilt by association used by McCarthy. Murrow's television show exposed the hollowness of McCarthy's unsubstantiated accusations, and he wanted to challenge the anti-Communist hysteria. By defending Radulovich, Murrow was sending a message that dissent should not be equated with treachery.