To examine the status of opinion as protected speech, a study sought answers to three questions: (1) Is opinion protected under the constitution? (2) If protection exists for opinion, has it usurped the common law fair comment defense in libel litigation? and (3) How do the courts define opinion in the context of libel? Answers were sought in Supreme Court and lower court cases dealing directly or indirectly with opinion. Findings indicated an overwhelming belief by courts at all levels that opinion is protected under the constitution; showed the predominance of the use of the opinion rationale over fair comment; and revealed seven approaches used by judges to determine whether allegedly libelous statements are fact or opinion, the most common being the "Restatement" rationale, in which opinion is protected unless undisclosed libelous facts are implied or present. The study recommends that journalists consider two major factors in establishing guidelines for everyday use: the context of the publication or broadcast; and the nature of the words in the allegedly libelous statement. (Eight tables of data and 160 footnotes are included.) (SR)