President Obama takes part in a briefing on the outbreak of the Ebola virus in West Africa, during a visit to the Centers for Disease Control and Prevention on September 16, 2014 in Atlanta, Georgia. Former Secret Service Director Julia Pierson was compelled to resign last month after a series of mishaps at the agency -- including an incident at the Centers for Disease Control and Prevention in which President Obama found himself on an elevator for a security guard armed with a gun.