Maj. Gen. Melvin Spiese (left), commanding general, 1st Marine Expeditionary Force, and Brig. Gen. James S. Hartsell (center), deputy commanding general, I MEF, speak to the captain of USNS Sgt. William Button near Camp Pendleton, Calif., during Pacific Horizon 11, March 3. Pacific Horizon 11 provides 1st Marine Expeditionary Force and the Navy's Expeditionary Strike Group-3 the opportunity to exercise essential core competencies at the brigade level to rapidly respond to an emerging crisis with a flexible, full spectrum capability.