On Killing is the title of a book by my old friend Lt. Col. Dave Grossman, and it is a book that anyone who has any interest in war should read. Obviously, killing is a central aspect of war, the aspect that distinguishes war from almost all other human endeavors.

Nonetheless, I find myself forced to disagree with a commentary one Marine infantry officer recently sent to the Fourth Generation seminar after he read the draft of our FMFM 1-A, Fourth Generation War. He wrote, “First, as tactical guys, killing is still the essence of the business. I think any manual written for Marines needs to take this into account as the bottom line.”

Again, killing always has been and is likely to remain a central aspect of war. But I would suggest that we should not define it as the “essence” or “bottom line” of war, especially Fourth Generation war. It seems to me that the bottom line needs to be, not killing, but winning.

If we define killing as our bottom line, then our understanding of war will lead us to kill, whether killing moves us toward or away from winning. One of the central points of our draft FMFM is that especially in 4GW, de-escalation, not escalation, is key to winning (the first of our seminar’s members to return from Iraq, where he was a company commander, said his experience there strongly supported that point).

While escalation and killing are not identical – in many situations, you may need to do some careful, limited, targeted killing in order to de-escalate – a bias toward killing could easily feed a tendency to escalate. (The officer who wrote to us added, “I do agree with the need for targeted killing – use a knife so to speak. This should be more the norm.”) Escalation, in turn, will almost always work in favor of our non-state enemies. In other words, at least in Fourth Generation war, winning and killing are likely to be in some tension with each other.

More, if we define killing as our bottom line, we fall back into Second Generation war with its inward focus. Third Generation “maneuver warfare” focuses outward, on the enemy, the situation and the result the situation requires. Defining killing as the “bottom line” is a form of inward focus, not in the sense of being one of the processes that are central to the Second Generation, but rather in seeing our ‘essence” defined as “what we do.” From a maneuver warfare perspective, what we do must always be infinitely flexible, based only on what the situation requires in order for us to win. Any form of inward focus contradicts maneuver warfare doctrine and undermines the institutional culture a Third Generation military must sustain.

It is easy to see why soldiers and Marines, “as tactical guys,” would define killing as the bottom line. Even in Third Generation wars such as the German “Blitzkrieg” campaigns of World War II, that was true of the tactical level (with the modification that German infiltration tactics, which date to late World War I, worked to bypass and collapse the enemy rather than kill him even on the tactical level; many of the enemy ended up POWs rather than dead). But one of the characteristics of Fourth Generation war is the compression of levels; a single tactical action can also work directly on the strategic level. We cannot normalize killing on the tactical level if it works against us on the strategic level, as in 4GW it generally will. Nobody wants to be “liberated” by being killed.

I am grateful for this Marine officer having taken the time to read our manuscript and write to use in response. The discussion he generated is exactly what the Marine Corps and our country need if they are to succeed in grappling with the dragon of Fourth Generation war. Nobody has all the answers, or even most of the answers, at this point. The most we can try to do is get the questions right, and open debate is the only tool through which we can hope to accomplish even that much.