The rapid deterioration of Russia–Ukraine relations in 2014 has reopened a discussion amongst European policymakers and experts about whether Putin's Russia can still be considered a reliable security partner. Russia's flagrant violation of the Budapest Agreement in annexing Crimea seems to indicate the opposite. Retrospectively, it looks as if Europe and Russia have missed their chance to transform the previous Cold War order into a trusted relationship. A new East–West conflict is on the rise, as even the mutual deterrence vocabulary of the past has re-entered the political stage. It is difficult to imagine how this conflict could be ‘de-escalated’ without tackling the underlying motivations and mutual perceptions on either side. Certainly, mistrust can hardly be negotiated away if the facts seem to tell the opposite tale. The current crisis management needs to be complemented by conflict transformation efforts. This paper elaborates how conflict transformation can help rebuild trust through cooperation.