When Google and Yahoo! forged an advertising pact in 2008, Thomas Barnett headed the anti-trust division of the US Department of Justice, which stepped in and torpedoed the deal.
Fast forward to today and Barnett, now in private practice, again has Google in his sights.
Barnett is serving as counsel for Expedia.com, which has joined with several other online travel websites in an effort to ground Google's proposed $700 million acquisition of flight information company ITA Software.
Expedia and other members of the FairSearch.org coalition are urging the Justice Department to block the Google-ITA deal -- just as it did in November 2008 with the Google-Yahoo! advertising agreement.
They are claiming that Google's purchase of ITA would give the Internet search giant too much control over the lucrative online travel sector and lead to higher prices and fewer choices for consumers.
"You're taking the dominant flight search engine company, which is ITA, and you're combining it with the dominant online search company, which is Google," Barnett told AFP.
"You're going to end up with a combined entity that will be positioned to come in and dominate the online travel search space."
Steve Kaufer, president and chief executive of TripAdvisor, an Expedia brand and ITA client, said competition is needed to keep airline ticket prices down.
"Fares stay low generally because consumers are able to find a wide range of fares from a wide range of airlines on a wide range of sites," Kaufer said.
A Google takeover of ITA could lead to "only one place to shop," he said, "and that might be good for Google but it's anti-consumer."
Other FairSearch.org members include Hotwire, another Expedia brand, Kayak and its brand SideStep, Sabre Holdings and its brand Travelocity, Microsoft, Foundem of Britain, France's Level and Farelogix.
ITA Software, a 500-person firm founded in 1996 by Massachusetts Institute of Technology computer scientists, specializes in organizing airline data, including flight times, availability and prices.