I've seen critics take issue with Trump's signature campaign slogan: Make America Great Again! They say compared to what? Then they trot out paradigm-cases of injustice.
They complain that Trump is appealing to a nonexistent golden age which he promises to restore, but such nostalgia is misplaced considering American history viz. Jim Crow, Japanese-American internment, the Trail of Tears, &c.
I'll make a two brief observations:
i) Campaign slogans are designed to fit on a bumper sticker. They are catchy, simplistic, and sometimes utter nonsense. Take Bill Clinton's reelection slogan: Building a Bridge to the 21C–as if the 21C wouldn't arrive unless we returned him to office. Time would be forever frozen in the late 20C.
I don't take campaign slogans seriously one way or the other.
ii) That said, I presume the implicit contrast in Trump's slogan isn't American history in general, or even 20C American history, but Obama's tenure. Make America great in relation to the previous administration. The target is the preceding eight years. That's the tacit comparison. The early 21C. Not 20C America, or 19C America, or 18C America, or 17C America. I think it's a willful or obtuse distortion to recontextualize the slogan as if the frame of reference is American history in general. It's obvious that he was running against some of Obama's controversial policies.