Employing the Defense in Maneuver Warfare

by Maj Joseph V. Medina

1990 Chase Prize Essay Contest Honorable Mention

Defensive tactics have never been “popular” with Marines, but knowing when and how to assume the defensive is crucial on the modern battlefield.

Marines, being naturally aggressive, shun the defense because it lacks boldness. We revert to it only as an economy of force measure that allows us to strike elsewhere or because weakness compels us to adopt it. To optimize our combat potential, however, we should seek to employ the defense in maneuver warfare for its strengths. When and how we decide to employ the defense is critical if we are to be successful in shattering the enemy’s moral and physical cohesion rather than just attempting to rack up more numbers to the enemy’s attrition.

Our focus of effort must be directed to wherever-or whatever-will cause the most decisive damage to the enemy. Often our focus of effort will be directed to the enemy’s obvious weak areas: his command posts, logistics support areas, communication sites, reserves, etc. However, there comes the time when our focus of effort should be directed against an enemy’s combat forces. This may be a result of a unique opportunity presented that must be exploited, because at this particular time and place this is his vulnerability or simply because the destruction of the enemy’s force has become, in itself, a decisive objective (as Paulus’ German Sixth Army became the Russian objective in the Battle of Stalingrad). The method of destruction is a critical decision the commander must make. A key technique, but one often overlooked for sheer destructive power, is to assume the defense.

Why do we have a reluctance to consider the defense, or to use defense techniques, when we are looking for destruction of the enemy? When we review what our own doctrine tells us, we find in FMFM 1 the following:

The offense contributes striking power. The offense generally has as its aim some positive gain; it is through the offense that we seek to impose some design on the enemy. The defense, on the other hand, contributes resisting power, the ability to preserve and protect oneself. Thus, the defense generally has a negative aim, that of resisting the enemy’s will.

This leads us to the conclusion that while the defense is the stronger form of combat, the offense is the preferred form, for only through the offense can we truly pursue a positive aim. We resort to the defensive when weakness compels.

Our own doctrine tells us that we must constantly strive for the offense in order to be victorious, and that we only assume the defense as a result of weakness-not to take advantage of our strengths. Although I embrace FMFM 1 as a welcome and needed change, there is more to the art of the defense than is reflected here. The defense can provide striking power, and can offer positive aim-that being the destruction of the enemy, his cohesion and integrity-if employed properly at the right time and place. We should consider assuming the defense to exploit our strengths and the enemy’s weaknesses. This is not to imply that we surrender the initiative. We must always maintain the initiative, especially when using the defense for a decisive stroke. This is the tricky part, but an essential element of employing the defense in maneuver warfare. Additionally, in contradiction to FMFM 1, in the defense we must seek to impose some design on the enemy. We must not be reacting solely to his offensive moves.

The destruction of an enemy force by assuming the defense is not a new concept. In fact, it has been employed by some of the masters of warfare, and a number of decisive battles were won by the defender. We need only look at Hannibal in the Second Punic War or, more recently, at MajGen Alexander A. Vandegrift at Guadalcanal. A brief review of these examples will help to better understand how the defense can provide us much more than an economy of force effort, and it should help to clarify employment techniques in maneuver warfare.

The Trebia to Cannae: A Lesson From Hannibal

A full 22 centuries ago, Hannibal engaged in a military campaign in Italy lasting 15 years. Fighting both the weather and the Gauls, Hannibal crossed the Pyrenees and the Alps in 218 B.C., arriving virtually undetected in the Po Valley of northern Italy. There he engaged and defeated every Roman force that rose to meet him. His first major battle against the Roman Legion, the Battle of the Trebia, is an excellent example of using defensive techniques for tactical success. After establishing a deceptively weak defensive position, Hannibal lured the hot-headed Roman leader, Sempronius, to attack across the freezing Trebia River, whereupon an effective counterattack struck the Roman flank and rear. The ensuing onslaught resulted in 30,000 Roman casualties. The following spring, after a surprise crossing of the snowy Apennine passes and a strenuous march through marshes thought to be impassable, Hannibal established his force on a narrow defile on the line of communication between the Roman army and Rome. From their position on the cliffs overlooking Lake Trasimene, the Carthaginians conducted the greatest ambush in history when they caught the Roman column moving to reestablish their link to Rome resulting in another 30,000 Roman casualties. At Cannae, Hannibal met a newly raised army of Roman and allied legions. In this tactical masterpiece of military history, Hannibal established a defense anchored on a bend in the Aufidus River. Although outnumbered by over two to one, he purposely weakened his center and strengthened his wings and allowed the overwhelming Roman infantry to push, but not break, his thinned center. At the decisive moment, Hannibal’s strong wings hit the Roman flank and rear, causing chaos and resulting in a complete slaughter.

What lessons can we take from these examples of Hannibal? The Carthaginian general fought his greatest battles at times and places of his choosing. His defense was never static, but relied on his greatest weapon-a swift, strong counterattack by a very capable force, his formidable Spanish, Gallic, and Numidian cavalry. He was not reluctant to change tactics and formations when he recognized the value of change; in fact, he adopted much of the Roman formations and tactical systems when he saw their superiority.

Guadalcanal: A Test of Determination

One of the best examples of a key defensive battle comes from our own history-the Guadalcanal campaign. What began as an offensive amphibious battle soon became a solid defense of the small perimeter surrounding Henderson Field. While there may be some argument whether this should be classified as a defensive campaign, this is best resolved by viewing the Guadalcanal campaign by stages according to Baron von der Goltz’s four variants of offensive and defensive action. The amphibious assault was assuredly an offensive action, both in the tactical and operational sense. However, after a successful landing, the operation turned to the tactical defense, guarding the airfield, but remained offensive in the operational sense. The initiative could very easily have slipped into Japanese hands, and only through active measures was Vandegrift able to retain it. These measures included continuous patrolling (even an attempted reconnaissance in force operation), limited objective attacks, employment of Marine aviation, constant adjustments in force dispositions and expansion of the perimeter, and pressure on the Navy for more active supporting operations. Vandegrift was not only able to achieve the first major operational success in the Pacific, he also made a sizable blow to the Japanese ground forces. The defense again moved into the tactical offensive in December 1942 after the 1st Marine Division was relieved by the XIV Corps, but by then the Japanese defeat was ensured. The defense of Guadalcanal should be reviewed in more detail, because only then will we understand the nuances of the defensive measures employed.

Employment of the Defense: Lessons Learned

Many other examples could be cited -Wellington at Waterloo, the Battle of Saratoga (Freeman’s Farm and Bemis Heights), Morgan at Cowpens, Jackson at Second Bull Run, Lee at Antietam, or Meade at Gettysburg; the list is extensive. By careful analysis of these examples we can see common threads which makes the defensethe stronger form of combat,” and makes it a technique we must keep in our professional bag of tricks for sheer destructive power and/or to gain a decisive edge over the enemy. A critical review highlights the following points:

* Offensive Action: The most effective defense employs many offensive techniques-often the distinction between offense and defense becomes blurred, as at Cannae. The reverse may also be true in that the defense may be employed as part of an overall offensive move. Care must be shown when taking up defensive positions to retain our offensive capabilities. Helmuth von Moltke the elder believed that:

A clever military leader will succeed in many cases in choosing defensive positions of such an offensive nature from the strategic point of view that the enemy is compelled to attack us in them.

We should look to combine the strategic offensive wilh the tactical strength of the defensive.

* Deception: Deception is a key element. The enemy should be of the opinion that he is gaining a decisive edge in his attack; he should believe he is going for our center of gravity or exposed critical vulnerability. In order to do this, we will have to plan the battlefield so that it creates the illusion of vulnerability, i.e., creating exposed critical targets (headquarters, communication sites, air command and control facilities, etc.) or key avenues of approach. However, we should never expect the enemy to do exactly what we desire (move along a specific corridor, for example), but rather we should attempt to create a situation that would allow us to anticipate his intent.

* See the Battlefield: We must be able to see the battlefield as it appears to the enemy as well as it really is, and we must optimize the use of terrain to our favor. Use of reverse slope defense cannot be over emphasized for, in effect, it represents a form of ambush. Use the terrain to best advantage, but never depend on the strength of terrain alone. (Remember Alexander’s favorite technique was to attack precisely where the terrain and fortifications appeared the most formidable.) We must select the terrain for its true advantage, not solely because it is the highest point on the map. (At Gettysburg, the Little Round Top proved to be the key to the Union line, not the larger Big Round Top.) Look at the microaspects of terrain.

* Combined Arms: Combined arms is a must in the defense. Consider the Cactus Air Force’s contribution to the defense at Guadalcanal. Conversely, the value of combined arms was a lesson forgotten by the Israelis prior to the 1973 Yom Kippur War when they overly relied on their armor and air forces to support the Bar Lev Line thereby neglecting their artillery and infantry arms. In this regard, a Marine air-ground task force (MAGTF) is uniquely able to capitalize on combined arms. More on this later.

* Static vs. Mobile Defenses: When we establish a defense, it cannot mean we become static or immobile even if we are defending a fixed feature (such as Henderson Field at Guadalcanal). To retain the initiative we must maintain contact with the enemy through constant patrolling at the small unit level, up to reconnaissance in force operations at the operational level. Other methods to consider are the use of helicopterborne forces for delaying elements or antiarmor teams, raids, etc. In the Iran-Iraq war, the Iraqi general Abed Al-Rashid attained distinction through his use of a mobile defense at the operational level.

* The Counterattack: Above all else, we must learn from these examples the value of the counterattack. As noted by Clausewitz, “A swift and vigorous transition to attack-the flashing sword of vengeance-is the most brilliant point of the defensive.” The counterattack force must be a strong, formidable force; in a defense employed out of strength, the counterattack force should be the main effort by design. It must have sufficient assets to deliver the decisive blow. Since the battle will unfold in an unforeseen manner, the counterattack force must also be highly mobile.

MAGTF Warfare and the Defense

The Marine Corps’ philosophy of employing all combat units as MAGTFs provides us more of an ability to optimize the strengths of the defense. When planning a defense, the MAGTF command element would be remiss if it did not give special consideration to the capabilities inherent in our aviation combat element (ACE). The concept of the defense should be planned at the MAGTF level, not by the ground combat element (GCE) alone. Airpower is relatively new; we still do not fully recognize this third dimension of warfare. Likewise, there can be no hard and fast rules, such as placing a fixed percentage of your combat power in reserve in the defense, because the defense must be planned around a ‘particular situation. Rather, let’s look at some ideas for employment of the MAGTF in the defense:

* Consider employment of the ACE as the main effort if your intent is the destruction of the enemy. Use the ACE to destroy the enemy’s command and control, strong armor reserve, and logistics support while simultaneously employing a supporting attack (possibly a separate counterattack force). This may entail attachment of a ground combat element to the ACE (possibly a battalion at the Marine expeditionary force level, or a company at the Marine expeditionary brigade level). It must be recognized that the supporting counterattack will have less than the degree of air support desired by the commander in this case.

* Consider holding one-third or less of your GCE in reserve, especially if the ACE is to be designated the main effort. The reserve force still has to have a high degree of mobility and lethality in order to exploit success to the maximum. Positioning of the reserve may also require special consideration; possibly placing it along a flank rather than behind forward elements.

* Consider a deceptive delaying action and follow through with a strong counterattack. Counterattacks are normally not a part of delay actions. If the enemy “reads” delay by your actions, then he should not expect a counterattack; consequently trip the counterattack at a most unexpected location.

* Consider assuming a defense following a successful offensive where you find yourself well behind the enemy’s forward elements. Once you are in an enemy’s rear area, you may find his critical areas well defended. It may be wiser to establish a defense along his line of communications at a location that makes him believe he must attack or wither on the vine.


The defense must always be based on a thorough analysis of the enemyhis strengths and weaknesses, his commander’s intent, a review of his recent actions, and his order of battle data. Only then can it succeed in enticing the enemy to some goal. Deception is a key; we must paint a picture of surfaces and gaps that expose the “vulnerability” that we desire the enemy to see. It must not only be plausible, it must appear irresistible. We must also analyze our own strengths and weaknesses, ensuring that the capabilities inherent within the MAGTF are optimized. Combining the tactical advantages of the defense with the force multipliers of full employment of the MAGTF, we have the capability to deliver a knockout punch. We should not fail to consider the defense because of our inherent reluctance to show weakness. Let’s plan wisely and consider assuming the defense out of strength.