Justice Brennan agreed with Justice Stewart that § 1464 should be construed to prohibit only obscenity. But he wrote separately because he believed the Court's First Amendment analysis was so fundamentally misguided that it required a response even if the statutory question should have ended the case.
He rejected the majority's reliance on the supposed intrusion into the home. A radio listener voluntarily turns on a public medium and can change stations or turn off the radio with minimal effort. That limited inconvenience, he argued, cannot justify suppressing speech that willing listeners want to receive.
He also rejected the protection-of-children rationale. Under prior cases, the government generally could restrict expression to minors only if it was obscene as to minors or subject to another legitimate prohibition. Carlin's monologue was not erotic or obscene, and the Court's rule risked reducing adults to receiving only material suitable for children.
The majority's rationales lacked clear limiting principles. They could support censorship of literature, political speech, news reports, or religious texts whenever offensive words were used and children might listen. Brennan believed the Court improperly entrusted the FCC and the judiciary with deciding which protected speech was sufficiently offensive or sufficiently valuable.
He disputed the idea that words can be divorced from their message. A speaker's word choice conveys emotion and meaning as well as abstract ideas, and alternative media may be more expensive, less accessible, or incapable of conveying the same message. In his view, the First Amendment left decisions about offensive speech to listeners and parents, not to governmental censors.