Strategic depth - always valuable?

Warfare is a tricky thing, and often defies simple ideas. One such simple idea is that more of a good thing is better, and much more is much better.

Reality doesn't agree every time.

* A small technological advantage may last for many years while a spectacular one may provoke an almost immediate reaction and be quickly de-valued.
* A numerical or firepower superiority often leads to inferior tactics because leaders resort to simple tactics because of their trust in their superiority.
* More infantry equipment weighs more and exhausts, even immobilizes infantrymen.
* Doing too much harm can be disadvantageous for the political goals of war.
* Amassing a huge army can lead to a logistical collapse and waste precious time (opportunities).

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Strategic depth is usually considered to be advantageous in warfare. An army with enough strategic depth (typically hundreds of kilometers between the enemy and the own capital) can "sell" ground for "blood", thereby exploiting the advantages of tactical defence and it can more easily survive failures. The French lacked sufficient depth to survive in 1940, while the Soviets had it in 1941 (among other advantages).

Depth allows to exploit the phenomenon of the culminating point of attack, a term coined by von Clausewitz. It means that an army becomes weaker during the attack up to a point where it's too weak and should revert to defence. Stepping over that point provokes a successful counter-offensive and disaster. "Schlagen aus der Nachhand" a.k.a. "mobile defense" is a tactic for the exploitation of such mistakes.

Depth was also very advantageous in earlier centuries when it was very difficult to supply an army over long distances on land. The Russians included depth into their defence both against Napoleon and Hitler as well as against less well-known invaders.

The requirement for depth was important not only for the operational level of war but also for peacetime political strategy; empires like Russia and Rome placed a huge emphasis on depth in order to protect their political and economic centres.

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I found reason to distrust the value of depth. I think it can mislead you into a trap just as many other military strengths can lead to failure.

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Let's look at this in a very abstract way; a scenario with three countries.

Country Red borders on country Yellow and consists of mostly closed terrain. Country Red is traditionally fearing invasions by country Blue and is about to re-define its grand strategy in regard to national defence.

Country Yellow was under country Red's control for many generations. It consists of mostly open terrain (mostly agricultural areas, few forests and cities).

Country Blue borders on country Yellow and is superior to country Red in air power.

The traditional approach would be to emphasize the importance of country Yellow as a supplier of depth for country A's defence strategy. Is this traditional approach still smart?

There are (at least) three reasons for doubts;
(1) Transportation technology has evolved and is able to bridge long distances on the ground in support of strong ground forces.
(2) Regaining dominance over country Yellow would cost a lot and especially increase the probability of a conflict between Red and Blue in the first place.
(3) Finally the most interesting problem: Yellow's territory is mostly open terrain and Blue is superior in air power - Red's forces would fight under disadvantageous conditions if fighting on Yellow's soil.

So Red could possibly exploit Yellows's territory as a buffer for added depth, but to use that buffer it would need to fight in the disadvantageous terrain of Yellow.

A strictly traditional approach that does not take into account modern factors could lead to a completely unnecessary and overall harmful political effort to regain useless depth.

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I pondered about this theoretical case in regard to Russia's Ukraine policy. There are of course many more factors at work in this real world example, but I wonder whether the (future) Russian military could make good use of the added depth at all.
Sadly, the "more depth is always better" thing seems to be deeply ingrained, quickly grasped and it also seems to be more an emotional argument, so reasoning won't leave much impression on the problem.

Sven Ortmann


  1. You left out, however, one of the critical variables in the equation: that is, what is the actual "cost" of increasing or establishing a strategic buffer? If the cost includes conquest and occupation, the buffer's value may be marginal. If, however, you can establish friendly relations with the territory and "buy" an alliance, it may be well worth the effort.

    Consider the Philippines. These islands have been the outer marker of US power in the Pacific since 1900. Occupying and controlling the Philippines directly proved to have monetary and political costs far greater than the strategic value of the islands themselves. As an ally, however, the economic costs (military and economic aid) are far lower and, from a political standpoint, whatever goes wrong on the islands can be attributed to inept local self-government.

    In fact, given modern geopolitics, it may actually be much more valuable to have a neutral territory on your frontier than an ally. Allies can be attacked and must be defended. If a neutral is attacked, however, it brings an international outcry and there is, of course, no explicit requirement to intervene. It remains an option.

    The US knows all about "free riders," nations that levy a claim on US power and protection while offering little in return but bases and occasional expressions of gratitude. If Ukraine were a territory of Russia, the revenues from the province may enhance Russian power, but only at a grave military and political cost. As an ally, they would require constant maintenance and expense. As a neutral they require only diplomatic politesse and yet offer very nearly the same benefit as an ally.

    It's possible the Russian campaign against NATO expansion envisions a buffer of neutrals in place of the old buffer of allies, but their effort seems almost as clumsy and bullying as the US eagerness to ring Russia with NATO members. A little honesty might actually be the best policy in this case.

  2. Indeed; I wrote this because I encountered some people who treated the "buffer" subject entirely emotional or as if it was a natural law requirement.

    Buffers (allied or neutral) have some value in national security policy, but you need to think about the actual value - not just assume it's indispensable because it's always been assumed to be indispensable.

  3. A very well written and succinct analysis - really quite though provoking. Im new here so ill be bookmarking you're site and visiting regularly from now on.