[1][2][3] Cooper served as a law clerk for Judge Abner Mikva of the United States Court of Appeals for the District of Columbia Circuit from 1993 to 1994.

[1] While in private practice, Cooper "represented diverse sets of clients in both criminal and civil investigations, with a focus on white-collar and anti-corruption matters.

[4][9] In a pretrial evidentiary ruling, Cooper denied Khattala's motion to suppress statements he made to FBI agents while detained on the Navy ship USS New York en route to the United States, a significant victory for federal prosecutors.

The challengers sought to invalidate Animal and Plant Health Inspection Service regulations affecting certain pet breeders who make Internet sales.

Cooper ruled that the counties lacked standing to pursue their claim, and wrote: "The Court is mindful of the vigorous debate in Central and South Florida over whether the express railway should be built.

The student sought to learn if the United States government was involved in Nelson Mandela's arrest and imprisonment in 1962, and filed suit against the agencies after each denied his FOIA request.

(The CIA asserted that the search would be "unreasonably burdensome" and the NSA gave a Glomar response, refusing to confirm or deny whether the agency had records involving Mandela).

[25] Cooper is married to Amy Jeffress, a former Justice Department official and national security counselor to former United States Attorney General Eric Holder.