Any conflict with a nuclear power like Russia carries the risk that nuclear weapons could be used, and President Vladimir Putin is aggressively exploiting such concerns. With its nuclear threats, the Kremlin is moving away from Russia’s doctrine that ascribes a protective role to its nuclear...

Replacing the US nuclear guarantee with a French nuclear umbrella for Europe would face major political and logistical challenges. Nevertheless, given the growing un­certainty in Europe and Asia, the German government should consider scenarios and options that go beyond today’s deterrence...