The 9 September events demonstrate two interlocking realities. First, the prospect of a NATO–Russia war is no longer an abstraction. Moscow has shown a willingness to test NATO directly. Second, the most likely path to such a conflict is not through deliberate escalation but through miscalculation. The means to a wider war exist; the question is which one. Technical failure, human error, or political panic could cause escalation to spiral in a single instant.