Justices of the Supreme Court may do a double-take on February 27 when they see who is arguing before them on which side in the arbitration case American Express Co. v. Italian Colors Restaurant.

The case pits the giant credit card company against merchants who want to pursue a class action antitrust challenge against the "swipe fees" they are forced to pay American Express.

Former solicitor general Paul Clement, usually a pro-business superstar of Supreme Court advocacy, will argue in the case—but not for the party you might think. Instead of representing business defendant American Express, Clement will stand up for the plaintiffs, including the Oakland, Calif., restaurant Italian Colors. He will argue that the arbitration agreements that merchants sign with AmEx should not prevent a class action from going forward, when case-by-case arbitration would effectively prevent plaintiffs from being able to vindicate their rights.

That is a pro-plaintiff position that a lawyer like David Frederick of Kellogg, Huber, Hansen, Todd, Evans & Figel might be expected to espouse before the court. But wait: Frederick’s partner Michael Kellogg will be arguing in the case for defendant American Express. The justices may need a scorecard.

Some Supreme Court advocates have grumbled about Clement’s new incarnation as a friend of plaintiffs seeking to limit arbitration in favor of class actions. They point to an amicus curiae brief Clement wrote in the similar 2011 case AT&T v. Concepcion on the pro-arbitration side of the fence. Clement’s brief for Italian Colors argues that the Concepcion decision, which favored arbitration agreements, is distinguishable from the issue before the court now. Other briefs, however, invoke Concepcion as a relevant precedent.

Asked if his representation poses a positional or business conflict of interest in light of his previous stance, Clement said, "I think that most of my clients, including my clients here, see my willingness to get involved in Supreme Court cases of many different types as an asset." When the Italian Colors clients first asked him to argue, Clement said, "We of course discussed my amicus brief in Concepcion. But it became clear that our arguments in Italian Colors would be made on narrow terms that make this case very distinguishable from Concepcion. I think the brief we filed reflects that initial vision and underscores that Concepcion really is very different."

Clement said similar questions were raised when he was asked to argue in last year’s landmark challenge to the Affordable Care Act, in which he articulated a limited view of the commerce clause power of Congress. As acting solicitor general in the 2004 case Gonzales v. Raich, Clement had argued for broad commerce clause powers. "I thought the cases were distinguishable, but I could see a client either viewing my role in Raich as a problem, or viewing me as the perfect lawyer to distinguish Raich," Clement said. "Either way, the important thing is for the client to make that call."

Compounding the oddity of Clement’s role is the fact that his co-counsel for Italian Colors is Deepak Gupta, the former Public Citizen lawyer who is name partner in the Gupta Beck firm in D.C. Gupta argued for the consumers in the Concepcion case.

Describing Clement as the "key advocate of his generation," Gupta said he too sees no problem in Clement joining his side of the Italian Colors case after being an adversary in Concepcion. "It is against type, a bit," Gupta acknowledged, but not a conflict. "He understands this is a very different case" from Concepcion, Gupta said, and his argument is not fundamentally anti-arbitration. Gupta added that Clement’s participation in itself will "underscore how this is different" from Concepcion, which is an important point to make. "The court pays special attention to what he does," said Gupta.

Two legal ethics experts also said Clement has violated no rules. "Many lawyers will not represent an interest adverse to the interests of other clients even when they can do so," said Stephen Gillers of New York University School of Law. "But this is their choice. And they can choose differently, as Clement has." Like Gupta, Gillers said that, in spite of Clement’s past stance, Clement’s current clients may see an advantage in hiring him for that very reason. "They may see him as especially credible because he is able to make fine distinctions."

THE LAWYER’S CALL

Some appellate advocates say that once they have "chosen sides" over the years in their practice—representing either plaintiffs or defendants—they would be reluctant to suddenly switch, even if they could. Said Gillers, "Some lawyers would not do it because they don’t want to alienate a valuable set of clients and a source of future work. But I imagine that Clement doesn’t have to worry about that, given his prominence."

Georgetown University Law Center professor Milton Regan said "the rules are fairly lenient" and allow lawyers to have "a certain amount of latitude" in representing a range of clients and views in the interest of maintaining their independence. If a lawyer presented starkly opposite arguments to the same tribunal, Regan said, judges might have "some concern," but, again, it is the lawyer’s call.

As for Kellogg, he has represented American Express in the Italian Colors litigation since it first appealed an earlier decision of the U.S Court of Appeals for the Second Circuit in 2007. He and others at Kellogg Huber often represent corporate defendants, especially in the telecommunications industry, while leaving David Frederick to develop his specialty of representing plaintiffs in pre-emption and other kinds of business disputes. Kellogg declined to comment.

Tony Mauro can be contacted at tmauro@alm.com.