The attritional war in Ukraine: a brief update

Updated Attritional Analysis: As of May 15, 2026

Preface: In February, I presented some estimates of the effects and timelines of the attritional war that is taking place in Ukraine. These estimates were based on modelling utilising a range of data available in the public domain. This short essay updates the assessment. In brief, three months after the February 2026 assessment, Russia’s replenishment advantage continues to support sustained, incremental but meaningful attrition, building pressure on Ukrainian positions. Ukraine’s net replacement rate remains near zero or negative amid acute manpower constraints and limited aid inflows. The upshot is that Russia’s onward march continues. The estimated timing of the mathematical tipping point — between July and September 2026 — coincides with a range of other pressures building globally and on the United States, not the least of which is the unfolding energy crisis occasioned by the war against Iran and the midterm elections of early November. The same caveats apply as per the original piece.

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Territorial and Operational Picture

Russian forces maintain methodical pressure on the Donetsk “fortress belt,” with notable intensity around Kostiantynivka. Local group of forces command estimates, reflected in Russian reporting, indicate control of approximately 50% of the city through infiltration tactics, footholds in southern and eastern districts, and incremental urban gains. Ukrainian accounts describe heavy fighting on the outskirts and in contested urban pockets but report continued resistance efforts. Progress remains grinding and localised.

Broader Russian estimates place overall Donbas control near 90%, with ongoing pressure toward Sloviansk and Kramatorsk approaches. Northern Sumy Oblast features continued border infiltrations and buffer-zone activity. Western Zaporizhzhia sees probing. These patterns reflect localised erosion of Ukrainian defensive density rather than uniform acceleration.

Losses and Replenishment

Body exchange ratios (frequently 25–35:1 Ukrainian to Russian in recent swaps) support elevated effective Russian infliction rates (β in the 0.0018–0.0025 range). Ukrainian manpower strains are pronounced, with understrength brigades (often 40–60% infantry), high AWOL rates, recruitment shortfalls, and efforts to lower the compulsory mobilisation age further toward 23. These steps signal deepening difficulty in generating sufficient replacements to sustain force density.

Russia recruited approximately 127,000 contract soldiers in the first four months of 2026 (averaging 800–1,000+ per day early before moderating), sustaining net r_R of roughly 500–800 lethal units per day after losses, supported by stocks and foreign recruits. Fire ratios of 5–10:1 in active sectors continue to amplify Ukrainian equipment and positional losses.

Model Update, Localised Tipping and Global Timing

Current Ukrainian effective force: ~320,000–380,000 lethal units (continued drawdown). Net daily loss rate: 900–1,700 units, aligned with fire dominance and body exchange indicators. Threshold density (coherence declining toward 65–73% of prior peaks) faces acute localised pressure, especially in sectors such as Kostiantynivka.

The original July–September 2026 tipping window remains realistic. Collapse will emerge through localised failures where Ukrainian reserves cannot contain concentrated pressure, rather than a simultaneous front-wide event. Kostiantynivka illustrates this dynamic where thinning density and partial control create conditions for potential southern exploitation toward Mykolaiv if connected with Zaporizhzhia/Kherson thinning. Parallel Sumy preparations lay groundwork for northern pushes that could eventually threaten the Dnipro line and Kyiv directions. These pockets would activate the non-linear multiplier (γ ≈ 2–2.5× losses) once containment is exceeded.

Sustained localised tipping (widespread breaches and accelerated positional losses) in 1.5–5 months from May (late June–October 2026), centred on July–September, remains the probable trajectory. This timeframe aligns with several external pressures: (1) ongoing global energy market dislocations from the Strait of Hormuz disruption (blocked since late February 2026), which have driven sharp oil price increases and inflationary effects that could constrain Western aid budgets and political bandwidth; (2) mounting scrutiny of highly valued US AI stocks amid concerns over infrastructure spending sustainability and potential valuation resets; and (3) positioning approximately two months ahead of the US midterm elections on November 3, 2026, a period when policy priorities and resource allocations often face heightened domestic review.

A number of oil market analysts, including Americans Art Berman and Chris Martenson, have pointed to the July-September window being a “crunch” moment for the U.S. economy, when inventories begin to run close to bottom, and replenishments — from seaborne and domestic production — simply doesn’t arrive in time. I have also explained previously why the U.S. is not immune from the impacts of the war in the Persian Gulf.

Put directly, Q3 2026 shapes as a vector in which multiple American exposures come home to roost.

These convergences could influence r_U parameters (e.g., via aid fatigue, political backlash in the face of rising gasoline or diesel prices or competing fiscal demands) without altering the underlying replenishment imbalance. Russian recruitment moderation adds modest variance, but Ukraine’s constraints dominate the ledger. The mathematics of attrition — superior Russian replacement flows (men, munitions and machinery) versus Ukrainian sustainability limits — drive progressive territorial erosion and set conditions for localised breakthroughs where defensive density collapses first.

Time favours the side whose reservoir refills faster. Like it or not, Putin’s confidence, evinced in his recent Victory Day speech, is warranted.