In 1984, the Supreme Court overturned the long-standing prohibition of editorials by noncommercial stations. Prior to the Supreme Court’s decision, stations were free to carry programs that presented the opinions of individuals or organizations, but could not themselves take editorial stands. The Supreme Court found the editorial ban to be a content-based restriction that violated the First Amendment.
FCC v. League of Women Voters of California, 468 U.S. 364, (1984).
Although there are no special requirements with regard to identifying station editorials, it is a general journalistic and broadcast practice to state when an opinion has been presented on behalf of the licensee. There are no special logging or Public File requirements for station editorials. The fact that FCC rules do not prohibit station editorials does not, of course mean editorials present no legal problems. Editorializing may implicate other laws such as state defamation law or IRS regulations related to grassroots lobbying.