"[I]nstitutions and communities need to be able to exploit their comparative advantages. It’s not just that the Marine Corps demands more from its members than the Peace Corps; it’s that the Marines demand different things. For some people, being a Marine would be a kind of living Hell; for others it is a reason to live. That’s what the individual pursuit of happiness means... You can’t choose to be a Marine if you do not meet the requirements, but you are free to try."