Harvard Belfer Center

The Harvard Belfer Center for Science and International Affairs is the flagship research centre of Harvard Kennedy School, founded in 1973. Based in Cambridge, Massachusetts, it focuses on nuclear security, geopolitical risk, and international diplomacy.

Its Russia Matters project tracks the Ukraine conflict and became a key source when its analysis of Institute for the Study of War (ISW) data revealed Russia had lost a net 33 square miles between 17 February and 17 March 2026: the first sustained Ukrainian net territorial gain since the 2023 counteroffensive. Russia's advance rate had decelerated fivefold since mid-2025, to 33-50 sq km per week by February 2026. By late May 2026, Russia Matters data showed the trend had accelerated sharply: Russia net-lost 100 square miles over the four weeks from 28 April to 26 May 2026, including a single-week loss of 38 square miles in the week of 19-26 May, the largest single-week Russian territorial loss of the year. Russia's net advance rate for January-May 2026 stood at only 104 sq km against 1,619 sq km in the same period of 2025.

The Centre's territorial tracking frames a central strategic question: whether Russia's mounting losses represent genuine reversal or a temporary pause. With Secretary General Rutte publicly characterising Ukraine as 'stabilising the frontline' on 21 May, the Belfer data has become a benchmark for policymakers weighing Ceasefire timing and Western support thresholds.