In a letter to the U.S. Department of Justice, the ANA objected to the Google-Yahoo partnership, arguing that it “will likely diminish competition, increase concentration of market power, limit choices currently available and potentially raise prices to advertisers for high-quality, affordable search advertising.” An understandable concern, considering that Google (GOOG) and Yahoo (YHOO) combined sell more than 80 percent of U.S. search ads, and more than 70 percent of that business is Google’s alone.

But not particularly understandable to Google, which likes to portray the alliance as some sort of enhanced AdSense deal that will make advertising on Yahoo more effective and Yahoo itself a “stronger competitor.” Unfortunately for Google, the ANA doesn’t share that view. Said Robert Liodice, ANA president and CEO, “We believe that the overall impact of this deal is a negative for advertisers and the marketplace.” A harsh indictment and one difficult for Google or the DOJ to shrug off when its coming from a group of companies that spend over $100 billion annually in advertising.