Reassurance and Deterrence after Russia’s War against Ukraine

Abstract

In response to Russia’s brutal, unprovoked, and expanded war against Ukraine in 2022, North Atlantic Treaty Organization (NATO) member states rushed support to help the latter defend itself, while the United States also reassured NATO’s eastern members that they would be defended in the event that Russia expanded the war into alliance territory. Since the start of the Cold War, extended deterrence has been a critical issue for scholarly and practitioner communities. How could the United States signal to Moscow during the Cold War and again today that it was ready to come to the defense of its treaty allies? Would the Kremlin believe the United States would risk damage, including a Russian nuclear strike, to its homeland to deter an attack on allies located far from US soil? Though alliance reassurance has received more attention in recent years, the subject remains far less studied than topics such as credibility among adversaries and extended deterrence’s impact on nonproliferation. What does it take to reassure allies that the United States will protect them in the event of an attack? Focusing on the interplay between resolve and capabilities, Brian Blankenship and Erik Lin-Greenberg argue that a feature of US policy since the Cold War, namely the use of relatively small numbers of