Members of the U.S. Secret Service's Counter Assault Team, known in the agency as CAT, are seen before boarding helicopters at a landing zone in Rijksmuseum in Amsterdam, Netherlands, on Monday. Pablo Martinez Monsivais/AP hide caption

itoggle caption Pablo Martinez Monsivais/AP

Mark Sullivan, Director of the United States Secret Service, at a hearing of the Senate Homeland Security and Government Affairs Committee in May of 2012. Brendan Smialowski /AFP/Getty Images hide caption

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Homeland Security Secretary Janet Napolitano as she testified this morning before the Senate Judiciary Committee. Mark Wilson/Getty Images hide caption

itoggle caption Mark Wilson/Getty Images