The ‘Extinct Volcanoes’ Problem: Why Unit Strength Is Not Combat Power

War is full of formations that exist more convincingly on organisational charts than on the battlefield. Ukraine’s struggle to regenerate brigades, Russia’s repeated rebuilding of depleted units and both armies’ dependence on replacement personnel have revived an old military problem: when does a unit cease to be a genuinely effective fighting organisation even though it continues to exist administratively?

The question has become particularly relevant for Ukraine. A recent RUSI assessment by Jack Watling described an audit of the country’s roughly 120 brigades in which around one-sixth were judged to be suffering disproportionately from poor leadership and sustained underperformance. One proposal was to consolidate weaker formations and transfer their personnel to better-performing brigades rather than continually replenishing organisations that remained ineffective. The same assessment highlighted another corrosive factor: units unable to rotate personnel adequately, leaving some soldiers in combat areas for periods of up to 200 days.

Svechin's Command of the 6th Finnish Rifle Regiment

This sounds like an intensely contemporary military-management problem. Yet Aleksandr Svechin confronted its essentials more than a century ago. While commanding the 6th Finnish Rifle Regiment during Russia’s Great Retreat of 1915, Svechin became fascinated by the difference between the nominal existence of a military formation and its actual ability to fight. His remarkable account of that experience, now available in English as The Art of Regimental Command: Lessons from World War I, is not simply a memoir of frontline service. It is an anatomy of what prolonged war does to military organisations.

Svechin organised part of his account under the striking heading ‘Extinct Volcanoes’. The phrase was not a decorative metaphor. It drew on Clausewitz’s image of battle as something that gradually burns itself out, leaving commanders to discover which forces still retain effective fighting energy. Svechin applied the image to formations that might continue to exist in orders of battle, personnel returns and headquarters calculations while having been hollowed out by casualties, exhaustion, weakened leadership, declining morale and prolonged friction. The volcano remains visible on the landscape. The fire inside it has gone out.

That distinction is worth recovering because modern militaries have become exceptionally good at counting forces and not always equally good at determining what those forces can actually do. When Svechin assumed command of the 6th Finnish Rifle Regiment in August 1915, its official returns provided impressively precise numbers. There were officers, more than 1,600 bayonets, hundreds of unarmed personnel, non-commissioned officers, telephone operators, scouts, machine-gun personnel, medical staff and supporting troops. The apparent precision concealed the real problem.

The regiment had been subjected to prolonged fighting and retreat. Its original machine guns had been lost. Its replacement weapons depended on ammunition for which there was no assured future supply. Personnel numbers alone could not capture the accumulated effects of exhaustion, losses, uneven replacements, disrupted organisation and declining morale. Svechin described taking over a very exhausted regiment while observing that many other Russian formations were in little better condition.

His insight was simple but important: strength is not the same as combat power.

This has direct relevance to assessments of the war in Ukraine. Analysts understandably track personnel numbers, brigades, battalions, vehicles, artillery systems, drones and ammunition. These are indispensable measures. But they can create an illusion of precision if detached from the quality and condition of the organisations in which those resources are employed. Two brigades of similar nominal size may possess radically different military value. One may retain experienced commanders and non-commissioned officers, functioning communications, cohesive sub-units, confidence and the ability to integrate fires and unmanned systems. Another may contain comparable numbers of personnel but lack the accumulated competence necessary to employ them effectively.

A Repository of Relationships

Recent Ukrainian experience illustrates this variation. Watling’s account of the debate over consolidating underperforming brigades matters precisely because it recognises that adding replacement personnel to a weak organisation does not necessarily repair that organisation. Modern armies often discuss regeneration through the language of replacement: replacing casualties, replacing equipment, restoring authorised strength and rebuilding stocks. These things are necessary. They are not sufficient.

A military formation is also a repository of relationships, experience and accumulated knowledge. Soldiers learn the habits of their commanders. Commanders learn the limits and strengths of their subordinates. Staffs develop procedures. Units acquire confidence from previous success or anxiety from previous failure. Informal networks emerge that enable organisations to continue functioning when formal mechanisms break down. Casualties consume this capital as well as manpower. Svechin’s writing repeatedly returns to precisely these human and organisational variables. His concern with officers, non-commissioned officers, morale, discipline, training and exhaustion was not an excursion away from tactics. It was his explanation of what made tactics possible.

This is also why prolonged exposure to combat matters so much. RUSI’s recent reporting on Ukrainian force-management problems notes the difficulty of rotating formations and the extremely long periods some personnel have consequently spent in combat areas. More broadly, the war has become one in which manpower challenges and prolonged attrition remain central pressures on both sides. Replacing losses may restore a figure in a personnel return. It does not instantly reproduce the knowledge of a veteran platoon commander, the confidence within a company, or the capacity of a battalion staff to interpret fragmentary information under pressure.

There is therefore a point at which repeatedly filling a damaged formation with replacements can become less effective than reorganising, consolidating or rebuilding it. Svechin’s extinct volcano is useful precisely because it forces commanders and analysts to ask when that threshold has been crossed. Svechin believed this could not be understood from headquarters returns alone. When his regiment was in position, he made a practice of moving among its companies and talking to the soldiers. He wrote that he concentrated on studying the men as much as the ground. The purpose was not paternalism. He needed to understand the instrument he was being asked to employ.

That knowledge had operational consequences. A commander who knows that a battalion has 600 men knows very little. A commander who knows which companies have lost their experienced leaders, which soldiers have begun to break under prolonged pressure, which junior officers retain the confidence of their men and which sub-units can still undertake offensive action knows considerably more. This is where Svechin’s argument acquires wider relevance for how Western militaries assess both Ukraine and Russia. Whisler and Kofman’s recent study of Russian force expansion reinforces the point: Moscow generated substantial additional mass, but increasingly failed to convert it into battlefield effect as force quality and the capacity to employ formations at scale declined. Russia can regenerate personnel and equipment without regenerating every formation equally. Ukraine can mobilise additional personnel without automatically converting them into coherent battlefield organisations. NATO armies themselves can maintain units on establishments that say little about whether those formations possess the personnel, collective training, reserves and supporting capabilities necessary for sustained high-intensity combat.

Required Assessments

The question should therefore not simply be: how many brigades does an army have? It should also be: how many of those brigades remain functioning military organisations? That requires assessments of leadership, cohesion, training, rotation, casualties among experienced personnel, staff competence, logistical condition, morale and the ability to integrate supporting capabilities. Some of these variables are difficult to quantify. That does not make them less real.

Indeed, treating what is easy to count as more important than what is difficult to measure is precisely how extinct volcanoes remain hidden inside an order of battle. Svechin’s lasting contribution was to understand that a regiment was not an entry on a military chart but a human organisation whose fighting power could be accumulated, preserved, squandered and finally extinguished. The extraordinary technological sophistication of the Ukrainian battlefield has not made that insight obsolete. Drones, digital command systems and precision fires have transformed how units find and strike one another. They have not eliminated exhaustion, leadership failure, declining cohesion or the organisational damage caused by prolonged attrition.

A century after Svechin commanded his regiment, military analysts still need to distinguish forces that exist from forces that can fight. Some volcanoes remain on the map long after they have stopped burning.

© Roger N. McDermott, 2026, published by RUSI with permission of the author.

The views expressed in this Commentary are the author's, and do not represent those of RUSI or any other institution.

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