Clarke was a Secret Service agent on President Charles Logan's protection detail during Day 5. After the Attorney General heard a recording of President Logan incriminating himself in the death of David Palmer and other crimes, he alerted men on the ground at Logan's eulogy for Palmer to take him into custody. When federal marshal Holtzman demonstrated to Logan that he had unknowingly been wearing a microtransmitter, and that he was under arrest, Logan demanded that Agent Clarke arrest Holtzman. Instead, Clarke assisted with the arrest of Logan. ("Day 5: 6:00am-7:00am")