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Jeb Bush doesn’t understand the concept of “dog whistle” politics.

Bush, speaking to MSNBC, continued his so far fruitless tirades against his bete noire Donald Trump, claiming that the GOP presidential front-runner, who recently called for barring all foreign Muslim visitors to the U.S., was throwing out “dog whistle proposals to prey on people’s fears.”

Say what you will about Trump, but he is not a dog whistler. Dog whistles are racially encoded messages that, on their surface, are just benign enough to give the speaker plausible deniability. Think of Richard Nixon’s appeals to “law and order” amidst political upheavals that included agitations for civil rights, or Mitt Romney’s vision of American society as divided between “makers and takers.”

What makes Trump different from other politicians is that he’s thrown away the dog whistle, made subtext text, and issued naked appeals to the worst prejudices of certain segments of the GOP base, who, much to the embarrassment of the GOP elite, apparently care nothing about the niceties of supply-side economics. That Bush is still struggling to understand this is one of the reasons he’s languishing in the polls.