Much of that was how America had always been. We changed it, many of us, through some of the proudest struggles of our history. It wasn’t easy, and sometimes it wasn’t pretty, but we did it, together. We won voting rights for all. We ended Jim Crow, and we pushed open the Golden Door again to welcome immigrants. We achieved full rights for women, and fought to let people of all genders and sexual orientations stand in the light. And if we have not yet created the America that Langston Hughes swore will be — “The land that never has been yet” — if there is still much to be done, at least we have advanced our standards of humanity, hope and decency to places where many people never thought we could reach.

What old men know, too, is that all that is gained can be lost. Lost just as the liberation that the Civil War and Emancipation brought was squandered after Reconstruction, by a white America grown morally weary, or bent on revenge. Lost as the gains of our labor unions have been for decades now, pushed back until so many of us stand alone in the workplace, before unfettered corporate power. Lost as the vote is being lost by legislative chicanery. Lost as so many powerful interests would have us lose the benefits of the social welfare state, privatize Social Security, and annihilate Obamacare altogether.

If he wins this Tuesday, Donald J. Trump would be, at 70, the oldest president ever elected. But there is much about Mr. Trump that is always young, and not in a good way. There is something permanently feckless and immature in the man. It can be seen in how he mangles virtually the same words that Langston Hughes used.

When Hughes writes, in the first two lines of his poem, “Let America be America again/ Let it be the dream it used to be,” he acknowledges that America is primarily a dream, a hope, an aspiration, that may never be fully attainable, but that spurs us to be better, to be larger. He follows this with the repeated counterpoint, “America never was America to me,” and through the rest of this remarkable poem he alternates between the oppressed and the wronged of America, and the great dreams that they have for their country, that can never be extinguished.

Mr. Trump, who is not a poet, either in his late-night tweets or on the speaker’s stump, sees American greatness as some heavy, dead thing that we must reacquire. Like a bar of gold, perhaps, or a bank vault, or one of the lifeless, anonymous buildings he loves to put up. It is a simplistic notion, reducing all the complexity of the American experience to a vague greatness, and his prescription for the future is just as undefined, a promise that we will return to “winning” without ever spelling out what we will win — save for the exclusion of “others,” the reduction of women to sexual tally points, the re-closeting of so many of us.