What scenarios do major Western think tanks forecast for the Russia‑Ukraine war in 2026?

1. Prolonged war of attrition — the baseline most think tanks expect

Several analytic products treat continuation of high‑intensity, attritional fighting as the most likely baseline for 2026: GLOBSEC’s multi‑scenario exercise singled out a “Prolonged War of Attrition” as the leading scenario for 2024–25 and extends that logic forward into 2026, giving it the highest probability among their set ^{[1] [6]}, while CSIS argues Putin intends to press an attritional campaign into 2026 to erode Ukrainian forces and hopes to force a collapse or capitulation even if that outcome is unlikely ^[2]. ISW’s operational assessments likewise depict ongoing high‑tempo operations, expanded drone salvos and preparation for future campaigns as consistent with a prolonged conflict ^{[3] [7]}.

2. Limited Russian tactical breakthroughs without strategic victory

Think tanks and OSINT analysts forecast continued Russian localized advances that yield territorial gains but not decisive victory in 2026: CSIS and ISW note Moscow’s tactical goals in Donetsk and expect incremental gains—Lyman, Pokrovsk, Myrnohrad and pressure toward Kostiantynivka and Huliaipole—without a front‑wide collapse ^{[2] [8]}. Independent reporting finds Russia made larger territorial captures in 2025 than in the prior two years combined, reinforcing expectations of further—but not necessarily war‑ending—advances in 2026 ^[9].

3. A frozen conflict or negotiated pause — plausible but politically fraught

Multiple analysts see a ceasefire or temporary freeze as possible in 2026 but warn it would likely institutionalize large Russian gains and create long‑term instability; Chatham House frames 2026 as a “battle of wills” where diplomacy could produce pauses but not durable settlement without major concessions and large Western commitments ^[4]. RFE/RL and UnHerd product analyses also judge an outright end to the war in 2026 unlikely, though a ceasefire producing a frozen conflict is a credible alternative trajectory ^{[10] [5]}.

4. Escalation and wider war — a lower‑probability, high‑impact scenario

ISW repeatedly flags the risk that a ceasefire or force redistribution could free Russian units to threaten NATO or spur covert attacks in Europe, and assesses that Russia could pose a meaningful threat to NATO earlier than many Western estimates if allowed time to reconstitute ^[3]. ISW’s operational reporting on strikes, Oreshnik missile warnings and Kremlin rhetoric underlines a scenario where miscalculation or force posture changes elevate the conflict beyond Ukraine’s borders ^{[11] [7]}.

5. Political, economic and alliance stress‑tests are central to outcomes

Think tanks stress that Western domestic politics and resource constraints are decisive variables: Chatham House estimates Ukraine will need roughly $100 billion in military and financial support to “hold the line” in 2026 and highlights the limits of transatlantic consensus, while Politico and UnHerd note that U.S. leadership choices and European cohesion will shape whether any negotiated outcome is tenable or whether the war stays protracted ^{[4] [12] [5]}. Russian domestic perceptions—such as polls showing many Russians expect an end in 2026—are cited as political wildcards but do not substitute for Moscow’s strategic calculus ^[13].

6. Where analysts disagree, and what the scenarios leave unresolved

Disagreements are mostly about timing and probabilities: GLOBSEC provides a multi‑scenario probability framework that places attrition highest ^{[1] [6]}, CSIS treats a catastrophic Ukrainian collapse as unlikely but non‑zero ^[2], and ISW emphasizes operational risks to NATO and the danger of reconstitution if fighting pauses ^[3]. Sources supplied here do not settle exact probability figures for each outcome beyond GLOBSEC’s internal scores, nor do they resolve how external diplomacy—especially U.S. administration policy—will reshuffle odds in 2026 ^{[1] [4]}.