In polite society, the most blatant forms of discrimination are usually considered unacceptable.
No reasonable mainstream politician would call for resegregation, eugenics or internment camps. However, the clever demagogue does not have to resort to saying what they intend, nor do they have to forgo pandering to an extremist base of supporters. This is where “dog whistles” come in.
A dog whistle is a coded term that has both a literal meaning acceptable in mainstream rhetoric as well as an obscured, second meaning meant to resonate with a “fringe” group. It is purposefully designed to initially seem innocuous, but have connotations that a targeted portion of the audience will recognize. When the connotations of the dog whistle are addressed, the speaker can deflect the accusations by resorting to the literal meanings of the terms.
One of the most famous examples of dog whistling was the rhetoric of Ronald Reagan, with his crusade against “welfare queens;” single mothers who supposedly took advantage of government assistance to live lavish lifestyles while leeching off the hard-working taxpayer. Reagan never explicitly mentioned race, but when white Southerners heard “welfare queen,” they instantly thought “black woman,” and this was far from unintentional. Reagan was signaling that he was the successor to the policies of George Wallace. This model of dog-whistling would be used by countless other politicians, both Republican and Democrat, up to the modern day.
This brings us to the current dog-whistling of Donald Trump and his cabinet. When Trump’s policy advisor Stephen Miller talks about restricting immigration to English speakers only, he can propose a policy that would overwhelmingly target people of color without actually having to say anything about race; similar to how “literacy tests” were used as a voting requirement to prevent people of color from voting.