Back in 2000, Ralph Nader ran a bunch of ads critiquing the corporate interests behind the Bush and Gore campaigns. To make his point, he used the style and some of ideas behind MasterCard's "Priceless" ad campaign -- specifically calling out the dollar amounts that corporate interests paid to candidates to secure their positions on the issues.
MasterCard sued Nader and his campaign committee, claiming that use of the ads violated copyright and trademark laws. My old firm, Fish & Richardson, defended Nader claiming that any similarity to the ads was protected by the fair use doctrine. Mastercard moved for a TRO against Nader and lost but continued to press the case toward trial.
Today, after four years of discovery battles and summary judgment briefing, the trial court ruled that Nader's use was, in fact, fair. A strong victory against overzealous copyright and trademark ownership and for non-commercial political speech.