Ed O'Callaghan is an American Republican lawyer, former co-chief of the terrorism and national security unit of the U.S. Attorney's office in New York, who resigned from the US Attorney's Office in July, 2008 to join John McCain's presidential campaign. One of three leaders of Sarah Palin's Alaska "truth squad," O'Callaghan became the public face of Palin's legal pushback against ethics charges related to her former brother-in-law, the so-called "Troopergate."
O'Callaghan moved into private practice in March 2009 when the law firm Nixon Peabody announced he had joined its Government Investigations and White Collar Defense Practice Group. In 2011, he joined the international law firm Clifford Chance in New York as a Partner in its White Collar, Regulatory Enforcement and Government Investigations practice group. Since joining Clifford Chance, O'Callaghan has worked on several high-profile representations, including Achilles Macris, who was head of the London branch of JP Morgan’s chief investment office, where the trader nicknamed the "London Whale," Bruno Iksil, worked;  Jeffrey Webb, the former President of CONCACAF and FIFA Executive Committee Member, in the criminal Racketeer Influenced and Corrupt Organizations Act (RICO) indictment pending in the United States District Court for the Eastern District of New York;  and Fokker Services, B.V., in the successful negotiation of a Deferred Prosecution Agreement (DPA) with DOJ involving historical violations of the U.S. sanctions, and related court proceedings in United States District Court for the District of Columbia and the United States Court of Appeals for the D.C. Circuit. The Fokker case represented a landmark victory that established important constitutional limits on judicial review of DPAs. 
Sarah Palin "truth squad"
O'Callaghan co-leads what the Anchorage Daily News calls "a cadre of high-powered operatives" described by John McCain's campaign as a "truth squad" to field questions about and push back on attacks against vice-presidential candidate Sarah Palin. (His two co-leaders are Karl Rove protegee Brian Jones and Washington lawyer Mark Paoletta.)
Paoletta, Jones, and O'Callaghan are "tasked specifically with responding to the sort of viral attacks that have been popping up about Palin’s background and record in Alaska...The public face for this pushback, though, will be woman Republican politicians, a 'truth squad' team designed to highlight attacks on Palin and draw sympathy to her side." Paoletta and Jones are volunteers while O'Callaghan is on staff.
Role in ethics investigation of Sarah Palin
O'Callaghan was sent to Alaska to handle "legal issues that are affecting the political dynamic of the campaign," according to Taylor Griffin, a former Treasury Department official in the Bush administration. Newsweek describes O'Callaghan's role as "helping to direct an aggressive legal strategy aimed at shutting down a pre-election ethics investigation into Alaska Gov. Sarah Palin." Working with Palin's attorney Thomas Van Flein, O'Callaghan worked to block the investigation. "There was no Ethics Act violation and there is no need to go forward with this," O'Callaghan told reporters.
The Alaska Personnel Board concluded that Palin did not violate the Alaska Executive Ethics Act by trying to get her brother-in-law fired. Alaska Personnel Board investigations are normally secret, but the three-member board chose to release its report one day before the Presidential election.
- March 2009 announcement from Nixon Peabody
- Anchorage Daily News (September 18, 2008) "Campaign fields Palin questions"
- Yahoo News (Sep 10, 2008) "Palin team stocked with Bush veterans"
- Atlantic (September 9, 2008) "McCain Campaign Stands Up Palin Truth-Squadding Team"
- Fox News (September 17, 2008) "McCain operatives flock to Alaska, head off embarrassing disclosures about Palin"
- Newsweek (September 16, 2008) "Can He Stop Troopergate?"
- AP report in Chicago Sun Times (November 3, 2008) "Report clears Sarah Palin in Troopergate"