Forms of ground mobility have gone through several changes. The horse and the various formations of what we know as cavalry once gave skilled commanders a shock effect to the immediate battle, as horse-mounted soldiers swiftly attacked less mobile formations. These commanders soon found cavalry also useful for longer-range operations and missions, such as positioning in the enemy rear, then attacking his homeland. One notable example was Colonel B. H. Grierson's cavalry raid from La Grange, Tennessee, through Mississippi, to Baton Rouge, Louisiana, from 17 April to 2 May 1863, during the American Civil War. (This was the Grierson who went on to command the 10th Cavalry, Buffalo Soldiers, in campaigns in the Southwest following the Civil War.) With 1,700 troopers of 6th and 7th Illinois and 2nd Iowa Cavalry, Grierson's deep-attacking force, according to
The arrival of rapid-firing rifles, machine guns, and more powerful, longer-range, accurate artillery soon called into question these horse-mobile formations in the increasingly deadly killing grounds of the close-combat battle. The idea of gaining a positional advantage, and the disruption it could bring to the coherence of an enemy formation, still had wide appeal, but the mobility to accomplish this was compromised, and then stopped, by the deadly fires of machine guns and artillery. Hence the stalemates of World War I. Not many battles of position. Just battles of brute force against brute force, hurling masses of men at each other in an attempt to break the firepower stranglehold of the other side. The cost in casualties, simply to gain and control even minor pieces of the enemy's real estate, became unacceptable. The result was the incredible human cost of World War I—8 million dead.
Military thinkers, especially in Britain, Germany, and Russia, looked for ways to restore maneuver to a battlefield that had evolved to gridlock.
What to do? The solution lay in developing mobile protected firepower, and then organizing these capabilities into formations that could operate with speed and combat efficiency on a battlefield dominated by defensive firepower. This became possible because of technology already available and in use during the early twentieth century, marking a convenient convergence of military war-fighting ideas and available technology.
Major technology available at the time included the internal-combustion engine, caterpillar-type tracked laying vehicles, wireless radios, and the airplane. The internal-combustion engine led, of course, to a transition from horse-drawn or steam-driven mobility in the civilian sector to power provided by these new engines to a wheeled base for mobility. Heavier vehicles that had to travel over unimproved ground, such as farmland and construction sites, soon turned to machines known as caterpillar crawlers or tracked laying vehicles. Though earlier versions of these caterpillar vehicles had been steam driven, new possibilities arose with the internal-combustion engine. Around 1908, it was demonstrated that a heavy vehicle could be mounted on two oval 'tracks.' Connecting these tracks to the power output of the internal-combustion engine propelled the vehicle over the ground. The vehicle crawled like a caterpillar, or rather the tracks were laid out on the ground for the vehicle to ride over.
Enter the tank, an effective combination of protection for the crew, mobility to move relatively quickly about the battlefield, and sufficient firepower to destroy enemy machines like theirs.
Unfortunately, early tanks did not work as well as their developers intended. Significant technical problems plagued their early designs, especially during World War I. Not the least of these were difficulties with crew- machine interaction (what modern-day designers call ergonomics) and a reliable track and suspension system.
It was a case where the ideas endured long enough for the technology to catch up. This is not always so, but it was in this case.
Back on the battlefield, now with tanks roaming over it, another piece had to be added, to prevent more chaos. That piece was voice communications. In an attack on the enemy, in order to permit some semblance of continuing organizational coherence, soldiers in tanks needed a means to talk to other tanks. Without such voice communications, it would prove difficult to impossible to keep coherent hundreds of noisy, tracked vehicles moving at various speeds over broken ground. At best, major formations of armored vehicles would have to rely on visual signals in order to remain grouped together, and would have to stop frequently to dismount and talk among themselves to change or adjust orders. Lacking the coherence gained from some kind of fast, dependable communication, the attacker would not be able to physically mass firepower when needed, or to change direction or type of maneuver.
By the late 1920s, wireless radios capable of line-of-sight transmission would permit individual tank commanders to communicate with each other and with their larger unit commanders. Such a breakthrough would allow control of attacking formations without the continuing need to halt, dismount, and communicate. Continuous operations would now be possible, as would the ability to adjust tactics rapidly, while retaining relative order and coherence of attacking formations.
Other wider-ranging possibilities soon became apparent to military theorists. For instance, they quickly saw that indirect fire support could come from longer-range artillery units in formations positioned to the rear of the immediate battle area. Target information transmissions from frontline mounted tankers would allow these units to deliver volumes of accurate and deadly fire in support of tank attacks.
Meanwhile, airpower advocates were discovering that the third dimension of airspace could provide external combat support. They recognized that the skies above the battlefield provided a positional advantage and an attack direction that could produce effects similar to cavalry, both in close-in battles and deeper in the enemy's rear. Observers on the ground looking at enemy targets could pass on the enemy location to aviators via radio. The aviators would then attack the enemy from the air, and further introduce chaos to the enemy. This concept was first used with devastating battlefield effect by the Germans with their Stukas, from 1939 to 1942, and later by Allied forces, notably U.S. ground and air forces of Third Army and 19th Air Force in 1944-45.
Three breakthrough war-fighting ideas significantly influenced the early design and experiments with mounted armored formations in the 1920s and 1930s.
• The first has become known as all arms or combined arms. According to all-arms theory, all combat, combat support, and combat service support functions should be mounted and be immediately available to the mounted commander. This would create a self-contained mobile force, with its own tanks, infantry, artillery, engineers, signal, and logistics (such as trucks for fuel, ammunition, food, and spare parts). Such an all-arms approach allowed the mounted commander to devise a variety of combinations of forces from within his own basic organization. Using these, he could exploit opportunities in changing battle situations without the need to constantly stop and reorganize. Skilled commanders could then conduct operations at a tempo of attack that brought them to positions where they presented the enemy with more situations than he could possibly handle in a given time and space. In this way, the initiative lost in the firepower-dominated battlefields of World War I was regained.
• The second of these theories held that mounted formations would attack dismounted or less mobile units, break through their front lines, then operate in their rear, destroying artillery, command posts, and logistics. Using the metaphor of a small penetrating stream that swiftly swelled into a flood, British theorist B. H. Liddell Hart named this theory the 'expanding torrent.' According to Hart's theory, the penetrating tank attack would have the effect of first destroying the initial line and eventually of collapsing the front…
Some later critics questioned whether Hart's theory was truly innovative, or whether it was merely an adaptation of the infiltration tactics adopted by both sides to break the deadly trench warfare grip on opposing forces mainly on the western front. In fact, many theories, and many tactics, were tried by military professionals to break this grip. By war's end, they had used every technology available at the time — not only armored forces, infiltration tactics, and air, but also, of course, chemical warfare. Original or not, theories such as Hart's became important for the inspiration they gave to later experiments in restoring the maneuver option. Hart was one of many such theorists, albeit one of the more prolific, readable, and influential writers. Other practitioners worked less noticeably in field experiments with the same goal.
• Third: In battle, it was now considered possible to fight both close and deep. This concept of a battlefield of much greater depth was proposed by Russian theorists, notably Tuchachevsky, in the 1930s. (It must be noted that many ideas were being rapidly exchanged between theorists in England, Russia, and Germany at this time.) Tuchachevsky theorized that it was possible with operational maneuver groups and air to create a zone of attack where you would simultaneously fight close and deep in the enemy rear, unlike during World War I, where units slugged it out along a line. 'Our technical equipment,' he wrote in 1937, 'enables us to put pressure on the enemy not only directly on the line of the front, but also to break through his disposition and attack to the full depth of the battle formation.'
