Did Coke Pressure King & Spalding?

According to some accounts, King & Spalding was persuaded to drop its representation of the House of Representatives in litigation over the Defense  of Marriage Act due to pressure from one of the Atlanta-based firm’s largest clients: Coca-Cola.  If this is true, it raises some interesting legal ethics questions that the good folks at the Legal Ethics Forum have been exploring, including Brad Wendel,  Rob Vischer, and Richard Painter.  One interesting point raised by Prof. Painter here is that any communications from Coca-Cola pressuring King & Spalding to drop the DOMA defense are unlikely to be privileged.  Indeed, under ABA Model Rule 1.4, King & Spalding could have to disclose such information to Congress.