The Supreme Court has had only a few occasions to address expression that mixes advertising with non-commercial messages, and the first was Bolger v. Youngs Drug Products. In that case, in addition to the “core notion of commercial speech” (“that which does no more than propose a commercial transaction”), the Supreme Court articulated a set of factors to determine commercial speech in “close cases:”
1) the advertising format of the message;
2) reference to a specific product; and
3) the economic motive of the speaker.[ref]Bolger v. Youngs Drug Products Corp., 463 U.S. 60, 65-68 (1983).[/ref]
While none of these factors alone will suffice to make expression commercial, the presence of all three provides “strong support” for a finding of commercial speech.
Two Supreme Court cases following Bolger added additional color to situations where commercial and noncommercial speech are mixed:
In Board of Trustees v. Fox, the court held that bolting a little political speech onto otherwise-commercial speech does not “immunize” the latter – it will be still be treated as commercial speech.[ref]Board of Trustees of the State Univ. of New York v. Fox, 492 U.S. 469, 474 (1989).[/ref] So you can’t add a political statement onto an attorney advertising billboard and expect to escape regulation.[ref]Or an ad onto editorial copy, as attorney Gregory Turza found out when he ended up on the hook for more than $4 million in damages for sending unsolicited faxes. Holtzman v. Turza ___ F.3d ___ (7th Cir. 2013).[/ref]
However, where the non-commercial speech is more than a mere appendage to commercial speech – where the two are “inextricably intertwined” – the communication will be treated as non-commercial speech, and entitled to full first amendment protection.[ref]Riley v. National Federation of the Blind of N.C., 487 U.S. 781, 796 (1988).[/ref] Such was the Court’s finding in the Riley case, in which solicitations from charitable organizations were deemed to be non-commercial speech.
The core principle to take away from this seems to be: all commercial speech is advertising, but not all advertising is commercial speech.
Unfortunately, the Supreme Court has never completely buttoned up whether there are any circumstances where the commercial speech doctrine should be applied to expression that is not in the form of advertising.