When a litigant wants to signal that it is quite serious about an appeal, one reliable method is to hire someone who has argued more than a hundred cases before the Supreme Court.

Elon Musk's X Corp. has done precisely that, retaining Paul D. Clement as lead counsel in its effort to revive the antitrust lawsuit against the World Federation of Advertisers and a roster of major brands, according to papers filed Wednesday with the United States Court of Appeals for the Fifth Circuit. Mr. Clement, who served as solicitor general during the George W. Bush administration, is widely regarded as one of the most accomplished appellate advocates of his generation.

The hiring comes roughly six weeks after Judge Jane Boyle of the Northern District of Texas dismissed the case in a 56-page ruling that found X's allegations, even if proven true, would not establish an antitrust violation. Her reasoning was brisk: the advertisers, she wrote, "merely decided that they would not buy from X for their own advertising needs," which is not the same thing as conspiring to control a market.

The underlying dispute dates to 2024, when X sued the Belgian-based federation and its now-defunct brand safety initiative, the Global Alliance for Responsible Media, along with a varied assortment of defendants including Mars, Nestlé, CVS, Shell, Lego and, somewhat incongruously, Pinterest. The complaint alleged that GARM had orchestrated a "massive advertiser boycott" following Mr. Musk's acquisition of the platform in October 2022, costing the company billions in revenue.

Mr. Clement's arrival adds a certain bipartisan credibility to the proceedings; he has represented conservative causes but also, more recently, law firms targeted by the Trump administration and tech industry groups challenging content-moderation laws in Texas and Florida. (Versatility, on the appellate circuit, is a marketable skill.)

The World Federation of Advertisers disbanded GARM last August, days after the suit was filed, though it has maintained that the initiative's brand safety standards were always voluntary.

The Fifth Circuit has not yet scheduled arguments. The case, whatever its merits, appears likely to continue generating legal fees for some time.

Original story published in MediaPost: "Musk Taps Former U.S. Solicitor General To Represent X In WFA 'Ad Boycott' Appeal"