ABSTRACT
Two duelling explanations have dominated the debate over Russia’s motivations for invading Ukraine. The realist position is that Russia has seen NATO expansion as an ever-growing security threat since the late 1990s and that it was only a matter of time before Moscow would use force to disrupt that process. No great power can abide a hostile alliance along its borders, and no bordering country was more important to Moscow than Ukraine. Hence the decision to invade Ukraine to undo its entanglement with NATO states and bring it safely back into Moscow’s orbit.
