BOB GARFIELD: Several years ago activists condemned Nike in the press for unfair labor practices overseas and convinced many people to boycott Nike products. When Nike's critics made their charges, accurate or not, they were and are protected by the First Amendment. Nike responded. In public statements, letters to the editor, press releases and newspaper ads the company defended the treatment of people working in overseas factories where it had contracts. Then San Francisco activist Mark Kasky brought suit against Nike charging that its statements on its labor practices amounted to false advertising.

BROOKE GLADSTONE:Now commercial speech in the form of advertising does not enjoy full First Amendment protection. It's regulated to protect consumers from fraud in ways that would be unacceptable for, say, political speech. Nike says that its statements about labor practices were not ads and so were fully protected. But the California Supreme Court decided that corporations can be held liable for misleading statements, even those made in error, because they might boost sales. And now the U.S. Supreme Court has announced that it will hear arguments in the Nike case. Should Nike enjoy the same protection as its critics? When a company issues a press release, even if it never mentions its products, it still hopes to encourage people to buy them. Is that commercial speech or not? Harvard University law professor Lawrence Tribe says no. He's representing Nike in its quest to overturn the California Supreme Court decision, and he joins me on the phone from his home in Cambridge, Massachusetts. Now I'm a big fan of your work, but I don't think I'm with you on this one, so-- see if you can convince me.

LAWRENCE TRIBE: I'll certainly try.

BROOKE GLADSTONE: If Nike wins and the ruling is overturned and it and other big corporations are given full First Amendment protection for speech that is ostensibly non-commercial, isn't this giving them greater latitude to lie or at least obfuscate?

LAWRENCE TRIBE: The reason that companies all around the world are worried about the chilling effect of that rule isn't that they want a license to lie; it's rather that they realize that the only way they can survive under a rule of that kind is to clam up completely.

BROOKE GLADSTONE: Or to be absolutely accurate in their statements.

LAWRENCE TRIBE:There's no way anyone can guarantee absolute and total accurate 100 percent of the time. That's why the U.S. Supreme Court in case after case has said that error must be protected if the freedom of expression is to have any breathing space. But there are plenty of protections against deception. I mean people who are deceived by a company can sue for whatever injury that deception causes. The Federal Trade Commission can go after false advertising, and a company has a lot to lose and not a lot to gain in the course of debate by putting out phony statements about conditions at its factories when you guys in the media are able to engage in investigative reporting and show that they're in some way making a misleading statement.

BROOKE GLADSTONE:I wonder -- would the California ruling really give activists and unfair advantage? I mean corporations have a lot more muscle to control public debate than the public interest groups that usually raise issues like these. Mr. Kasky was a consumer advocate. It strikes me that if anything this ruling levels the playing field a little bit.

LAWRENCE TRIBE: Well, look, as somebody who is myself not generally sympathetic with the position that huge corporations take in their labor-management relations and who wouldn't mind seeing the playing field leveled, I have to tell you that I think that the way it'll be leveled is through a massive silencing effect. I mean Nike, for example, decided -- and I think had to decide -- that it was simply not going to release anywhere in the world its next annual corporate responsibility report --couldn't afford to because it could be subjected to any number of Kasky-like lawsuits which would be crippling. So the net effect, and, and I think the reason the New York Times and the Washington Post and CNN filed amicus briefs on Nike's side was that they realized the net effect would be that journalists would find their sources drying up when they tried to find out stuff from these companies! It seems to me that the way our system works is we have debate about those matters!

BROOKE GLADSTONE: But I refer back to that currently extremely un-level playing field.

LAWRENCE TRIBE:We're not talking here about the power a state might have to deal with provably deliberate falsehood. We're talking about strict liability without any proof of any deliberate wrongdoing, deliberate lying - even negligence, and I think is an important difference. But I appreciate the broader point you're making. In our society the playing field is not level in a lot of different ways, but I think taking the mal-distribution of wealth and power into account is a very tricky thing if what you're doing is taking it into account by giving government officials the power to say what's true and what isn't true! I think there can be a vigorous debate about whether the net impact of globalization is positive or negative on people in the Third World, but I wouldn't want anyone to claim to have the power on your behalf or on my behalf to give the final answer as to what, you know, what is the truth of the matter on issues of that kind where fact and opinion inevitably blend. It's -- That's very different from selling a pair of shoes; I mean if somebody says here's a pair of sneakers and you know they're made of the following ingredients, I, I expect not to be deceived. But if somebody says the people who made these sneakers were fairly treated and says that in a letter to the editor or in an on-air interview, the idea that that can trigger what amounts to a kind of inquisition in a California court in a lawsuit by any of 34 million citizens really does frighten me.

BROOKE GLADSTONE: Well thanks very much.

LAWRENCE TRIBE: Okay! I don't know if I've persuaded you. [LAUGHS]

BROOKE GLADSTONE:[LAUGHS] I'm a little closer now. Lawrence Tribe will make the oral argument on behalf of Nike before the Supreme Court on April 23rd.

BOB GARFIELD: Coming up, the birth of public relations and commercials that hide in the evening news.

BROOKE GLADSTONE: This is On the Media from NPR.