My apologies to Jack for jumping to conclusions, and to Q for crediting his words to Kevin.

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The Wikipedia page for dog whistle http://en.wikipedia.org/wiki/Dog-whistle_politics defines them as "a type of political campaigning or speechmaking which is employs coded language that appears to mean one thing to the general population but has a different or more specific meaning for a targeted subgroup of the audience. The term is invariably pejorative, and is used to refer both to messages with an intentional subtext, and those where the existence or intent of a secondary meaning is disputed."


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The author/s of that page indicate that the phrase "dog whistles" as defined above originated in Australia. Examples are included on that page about the use of coded references or "dog whistles" in Australia, the United Kingdom, and in the USA.