Plenty of pundits have weighed in on the electoral implications of British Prime Minister Boris Johnson's recent landslide victory, but fewer have addressed its strategic implications for the United Kingdom's position in the world. In part, I suspect, this is because there are few obvious analogies for the political crisis Brexit has precipitated, and, without historical comparison cases, forecasting too easily becomes guesswork. There is, though, one suggestive parallel for what Britain is going through. Extrapolating possible futures from an isolated analogy is open to obvious objections; however, it is surely better than working without comparisons of any kind -- and it prompts some sobering thoughts....