Deference to senior command is a hard-wired tradition in elite military organizations, and nowhere is that tradition more honored than in the U.S. Marine Corps. But what happens if a policy coming from the top of the chain of command is insufficiently tested or intrinsically flawed? Where is it written that a subordinate or former commander can set aside deference and demand a second look? For more than two years many of the Marine Corps’ finest former leaders have struggled with this dilemma as they quietly discussed a series of fundamental changes ordered, and in some cases already implemented, by...