You've probably never heard of Dave Berger. President Trump nominated him on March 27 to be the 38th commandant of the Marine Corps. I met him when we were both assigned to Camp Pendleton, and I remember his deep interest in mastering the Corps's tactics, logistics, and weapons systems. From the beginning of his career, he showed a quiet devotion to the Corps's excellence. His career is filled with aggressive, on-the-ground combat, including leading a regiment at Fallujah and a division in Afghanistan. He is one of America's best and most experienced combat commanders. The Berger nomination is in contrast...