The latest policy proclamation from President Donald Trump: “We are going to have the Air Force and we are going to have the ‘Space Force’ - separate but equal, it is going to be something so important.”


Notice anything odd?


At present, the Trump administration’s policy of separating families at the southern border is not being warmly received by the public. Perhaps having noted that fact, the president attempted to create a distraction Monday afternoon with a surprise announcement outlining his desire to create a sixth independent branch of the military - the Space Force.


But as bizarre as the concept of this new force was the phrasing used to describe it: “separate but equal.” What could that possibly mean in this context? And which communications person let that slip in?


Most likely nothing - and none. By this point, three years into his reemergence on the public stage, we know how Donald Trump gives speeches. They’re spur-of-the-moment word association, a stream of consciousness often completely divorced from any suggested script. Even so, they manage to somehow work in particular phrases and references uniquely suited for maximum stickiness with a predetermined base.


What is most curious is how the phrases that occur to Trump, even if wildly inappropriate for the context at hand, all oddly hang together - this latest included. Trump is no historian, but the slogans he prefers all have history in common.


“Separate but equal” is a segregation-era term - one that most Americans are trying to put behind them, not delightedly apply to the armed forces. The idea that demanding nonwhites use separate facilities was not discrimination, as long as the facilities were equal, was deemed constitutional in 1896, in Plessy v. Ferguson. That obvious inequity was finally overturned by the Supreme Court in 1954 in Brown v. Board of Education, but not without the doctrine of separate but equal being used in the interim to obscure - and justify - horrifying amounts of discrimination. The aftereffects still linger today, especially in our education system.


Another Trump administration favorite is “law and order,” a holdover from Richard M. Nixon’s 1968 campaign. Candidate Trump reclaimed it in 2016 and has been repeating the term ever since. It’s not about actual law and order, of course (otherwise, something would have to be done about the array of grifters and criminals parading through the White House and Cabinet), but about creating a perception of growing crisis. The purpose of the term is to spawn nightmares of violence and criminality, controllable only from the top down. And it’s best applied in a racialized manner - to “illegals,” immigrant “animals” and purveyors of inner-city “American carnage.”


Which brings us to “America First,” the phrase that rolls off Trump’s tongue - and Twitter feed - with a gleefulness that belies its distasteful history. That particular slogan rose to prominence around 1915, when President Woodrow Wilson used the phrase to defend American neutrality in World War I. Its nativist undertones lent it credibility as a Ku Klux Klan slogan, and, grounded in nationalism and xenophobia, the phrase was again famously deployed by anti-Semite Charles Lindbergh to advocate for keeping America out of World War II.


Was “separate but equal” an unfortunate slip of the tongue? Maybe, but maybe not. What Trump’s go-to word associations have noticeably in common is that they are all phrases of division, plucked from the uglier chapters of the past century of American history. They are racialized. And they are used to stoke a fear of the other while promoting self-serving - Trump-serving - ways of quashing dissent and asserting authority.


Just a day after using “separate but equal,” Trump branched out to using shameful episodes in other countries’ recent histories to supply the vocabulary for his spur-of-the-moment public statements. In a tweet Tuesday morning, he attempted to lay the family separation policy at the feet of Democrats, saying that “they don’t care about crime and want illegal immigrants, no matter how bad they may be, to pour into and infest our Country, like MS-13.” An outside population “infesting” a nation, like vermin. Where have we heard that before?


Trump’s flights of language are bizarre but not entirely accidental. This Space Force announcement should remind us that even when our administration talks about the future, we should beware attempts to pull us back into the past.


Christine Emba is a columnist with The Washington Post.