The newly appointed second-in-command at the U.S. Justice Department faced a weighty task just two weeks after taking office — writing the rationale for firing FBI Director James Comey.

Deputy Attorney General Rod Rosenstein argued the case for Comey's sacking in a three-page memo to Attorney General Jeff Sessions on Tuesday. President Donald Trump acted swiftly to dismiss the director later that day.

Rosenstein cited Comey's controversial public statements about the bureau's investigation into Democratic presidential candidate Hillary Clinton's use of a private email server while she was secretary of state.