One of the greatest tactical challenges for a commander is the defense of open terrain with little or no vegetation and relatively flat landscapes, such as deserts and steppes. Although not a predominant feature in the world, open terrain has often been the battleground in key conflicts of the 20th century—Flanders, Palestine, the Steppes of Russia, North Africa, Sinai and the Persian Gulf. Theoretically, the defense of such terrain is best suited for mechanized forces fighting great mobile battles. The reality, however, is that dismounted forces must often establish defenses in this terrain without the capability or latitude of grand maneuver. Holding a front line or protecting an operational flank, key port, lodgment area or pass dictates that certain areas must be held with little chance for operational maneuver. The great tactical dilemma for dismounted forces is defending in such terrain against the greater firepower and mobility of mechanized forces.The plight is apparent once the local commander surveys his prospective defensive sector. Conventional defensive dispositions seek to maximize the standoff capabilities of weapon systems. The attacker has little problem identifying these key weapon positions because they are located on prominent terrain and easily pinpointed with the commencement of weapons fire. The vastness of open terrain allows little opportunity for economy of force or secured flanks. To cover a sector adequately, the commander must extend defensive positions, which in turn dilutes the concentration of fires and obstacles. Moreover, the commander must figure a way to cover an open flank if one exists. Correcting these deficiencies by increasing the troop density in the front line may ensure retention of a sector, but it also leads to exorbitant casualties. In short, the defense resembles the proverbial “thin red line.”For a mechanized enemy, the opportunities for success abound. Enemy reconnaissance can observe defensive activities from a distance. Often the openness of the terrain deludes the defender into concluding that intruders will be easily discovered. In reality, competent reconnaissance teams can exploit the many folds and depressions in apparent flat terrain and avoid detection even within the defensive sector.Once the reconnaissance locates weaknesses in the defense, the attacker takes advantage of the few movement restrictions to close, shift and mass forces rapidly at the decisive point. The ubiquitous support-by-fire (SBF) positions allow the attacker to support the points of penetration at any portion of the defense. A combination of smoke, indirect fire and SBF positions also allows him to obscure and suppress any portion of the defense that attempts to withdraw or support the threatened sector. Moreover, SBF positions normally are part of an intervening 2 terrain feature (slight ridge, sunken road or inter-visibility line), allowing the attacker to shift his forces under cover. In this manner, the defenders have few opportunities for flank and rear shots. The majority of fires will hence be frontal shots. The importance of this advantage cannot be overstated. With the majority of the force devoted to overwatch, only a small portion is devoted to the assault. Attrition is kept to a minimum, and even if the assault is repulsed, the attacker can simply shift to another point. Once the defensive line is penetrated, the attacker can easily roll up both sides of the breach to widen the shoulders since defensive orientation is to the front and incapable of reorientation. Ground and air reconnaissance can quickly identify the movement of any mobile forces (armor attachments or reserve) and suppress them with aerial, artillery or chemical munitions. At this point, exploitation renders further defense problematic.None of the aforementioned disadvantages is new. Armies have been grappling with this tactical problem with mixed results since World War I. The Germans appear to have been the most successful and to have devoted the most thought to the development of a successful defensive doctrine in open terrain—the Elastic Defense. The purpose of this study is to examine the evolution of the Elastic Defense and adapt it for modern combat as the Resilient Defense. Executed within the framework of dispersal and depth, cover and concealment and tactical agility, the Resilient Defense will not only repulse a mechanized attack in open terrain but do so with minimum losses.