A prominent military thinktank has issued a stark warning that Russia possesses the capability to sustain its full-scale invasion of Ukraine throughout 2026, despite emerging economic and manpower pressures. The International Institute for Strategic Studies (IISS) indicates there is little sign Moscow's capacity to wage war for a fifth consecutive year is diminishing.
Russia's Sustained Military Capacity
Bastian Giegerich, director general of the IISS, emphasised there is "little indication" that Russia's ability to continue its war against Ukraine has weakened. This assessment comes as the Kremlin reoriented its economy towards wartime production following the launch of the invasion four years ago.
Defence Spending and Economic Pressures
The thinktank's analysis reveals Russia allocated at least $186 billion (£138 billion) to defence in 2025, representing a 3% increase in real terms. This expenditure amounts to 7.3% of the country's GDP – more than double the proportion spent by the United States and approximately three times the level of the United Kingdom.
Fenella McGerty, a defence finance expert with the IISS, noted that while Russia's economy is slowing, which could lead to "a potential decline" in real-terms military spending in 2026, this must be viewed against several years of sharp growth. Military spending has doubled in real terms since 2021, enabling Russia to invest heavily in military equipment and recruitment to sustain relentless ground and air attacks against Ukraine.
Manpower Challenges and Casualty Rates
Nigel Gould Davies, a Russia expert at the thinktank and former UK ambassador to Belarus, highlighted growing signs that Russia's monthly recruitment rate has begun to fall short of battlefield losses. Moscow currently recruits an estimated 30,000 to 35,000 people monthly, but Gould Davies suggested recruiters are increasingly turning to "the alcoholics and the drug addicted, and the frankly sick", resulting in declining forces quality.
Estimates of Russian casualties vary, with UK Ministry of Defence figures suggesting 35,030 casualties in December and 31,713 in January – somewhat lower than the "nearly 40,000 a month" cited by western officials. Gould Davies warned that if this recruitment trend continues, it could eventually force the Kremlin to a "moment of truth", risking a second enforced mobilisation similar to September 2022, which could provoke significant social unrest.
Evolving Military Tactics and European Threat
The thinktank reported that Moscow is using the conflict to develop new battle tactics, missiles, and attack drones. This includes a modernised Shahed-136 drone capable of striking targets across Europe with a range of 2,000 kilometres. Giegerich underscored the need for NATO to increase investments in missile defence and anti-drone systems, particularly after 21 Russian drones crossed into Poland last September, closing several airports and forcing residents in three regions to shelter indoors.
NATO's Response and Challenges
European NATO allies and Canada pledged to increase defence budgets to 3.5% by 2035 last summer in response to the growing Russian threat and demands from the Trump administration for the continent to assume primary responsibility for its security. However, the IISS cautioned in its annual review, The Military Balance, that achieving this target would require "sustained and significant investments" many allies may find difficult, potentially necessitating spending cuts and trade-offs elsewhere.
Giegerich added that Europe would take "well into the 2030s" to reduce its military dependence on the United States, as it remains reliant on an unpredictable White House for military intelligence, cloud computing, and space assets. Improving air defence systems remains a critical priority for the alliance.
Despite western discussions about sustainable ceasefire agreements, Russia continues to intensify attacks on Ukraine's critical infrastructure and population centres using a mix of cruise and ballistic missiles and one-way attack drones. The thinktank's comprehensive analysis paints a picture of a conflict with no immediate end in sight, with Russia demonstrating both the economic resources and military adaptability to continue its campaign through 2026 and beyond.
