Historical analogies are more usually drawn during international crises. Every minor dictator, including Nasser, Galtieri, Saddam and Ahmadinejad is immediately compared with Hitler, even though he led a heavily armed industrial state in the heart of Europe and took on three major powers. Anyone who seeks to deal with these "Hitlers" through diplomacy, international institutions and sanctions finds themselves reverted to Munich in 1938, while the mantle of Churchill is blithely assumed by those who wish to send young men into battle. Every military intervention by the US is invariably referenced back to Vietnam, quagmire of, even though modern technology has enabled the US to end the purely military part of such conflicts with extraordinary rapidity. The history of counter-insurgency wars, from the Rif to Malaya or the Philippines, would surely be a better point of comparison for the problems which ensue after the major war fighting is over.

Why do so many people accept such analogies? They surely reflect a nation's psyche, even when the experience of one country (say Britain and France in the 1930s) is actually being incorporated into that of another, as has happened with fears of appeasement in the US. 

Looking to the past is part of any nation's sense of identity, whether for lessons to avoid or stirring examples to pursue. Simon Schama and David Starkey have built careers as pundits out of what are at best tenuous analogies with the remoter past and our present and future. The grim, thuggish, bureaucratic reality of Labour is unnecessarily dignified by comparing it with machinations at the court of Henry VIII. 

Historical analogies also provide us with a reassuringly manageable cognitive map or route through a chaotically frightening present. Although there are significant differences between, say, parochial Irish Republican terrorists and the global jihadists, some take comfort in the delusion that a peace process lurks behind every corner. Everything can be negotiated if reasonable men sit down and settle. If it can't, then the "spirit of the Blitz" will see us through, even though "then" enemy aliens and Nazi sympathisers were also quarantined in internment camps and prisons. 

For that is surely another reason for historical analogies. Our country is so partially and poorly informed about foreign affairs, not least by the likes of John Simpson, that it needs to be mobilised around sentimentalised snippets of a past it also hardly knows, which on closer inspection was less sentimental about our enemies than we like to think.