It was such a marvelous idea: the United States of America.

Obviously, we’ve never really pulled it all together under one hat, but it has always seemed that at least we were striving for a more perfect union.

No more. Something changed — and quickly, as history goes. Actually, everything did.

Massive immigration has changed the face of the nation in more than metaphorical ways. Globalization has made us seem or at least feel less unique among nations. Our hyperpartisanship, augmented by incessant media coverage tied to ratings and greed, has reduced politics to a parking-lot brawl.

Republican presidential contender Donald Trump said on Dec. 7 that he was in favor of a '"total and complete" shutdown of Muslims entering the United States. (C-SPAN)

Demographic slicing and dicing is essential to elections, of course. Analysts and operatives are especially attached to the segmented sets of individuals, the better to objectify them into manageable parts and, thus, to predict or win elections.

This much is understood and has been so constantly discussed and written about that we’re nearly out of oxygen and ink.

Less well understood is how these ceaseless reductions affect the whole. How do we sustain our unitedness when our dividedness is relentlessly articulated and shrewdly used to turn one against the other? Uniting 50 states is hard enough without the many variables that combine to make up an individual, a group, a class, a community and, ultimately, a voting bloc.

One nation, indivisible, my eye.

Every now and then, the Ad Council, Benetton or some other group will remind us that we’re all one people. “I am an American,” says a gentleman sporting a sombrero. “I am an American,” says a woman wearing a nun’s habit. Or a rainbow row of children wearing adorable togs will make us want to adopt the world.

They make us smile. We feel good. America rolls along. Or do we? Such ads are propaganda by any other name, idealized versions of what we’re supposed to be. But there’s nothing multicultural about what Donald Trump is selling. And though he may have pots of gold, rainbows run away when The Donald’s dark scowl appears.

In fact, Trump and his minions don’t want a united nation. What they want is their country back, or, in the slicker slogan, to “make America great again.” Translation: They want their majority-white, Anglo-Saxon, Judeo-Christian country back.

1 of 10 Full Screen Autoplay Close Skip Ad × 10 celebrities who say they’ll leave the U.S. if Donald Trump is elected president View Photos From Jon Stewart to Cher, some said they’d move to Canada, but some preferred another planet. Caption From Jon Stewart to Cher, some said they’d move to Canada, but some preferred another planet. Jon Stewart After the Emmy Awards in September, Stewart was asked whether he’d consider returning to "The Daily Show" if Donald Trump is elected president in 2016. “I would consider getting in a rocket and going to another planet because clearly this planet has gone bonkers," he said. Chip Somodevilla/Getty Images Buy Photo Wait 1 second to continue.

This is never going to happen, and yet Trump never admits it. He isn’t going to round up 11 million people and send them back whence they came. He isn’t going to block Muslims from entering the United States. But it seems to please his base for him to say so, and it doesn’t seem to bother Trump that he’s fibbing. What anyone seeking to become president at these dicey times must answer is: How do we adapt to our changed world to become a united nation once again? With so much stridency and drama, it’s hard sometimes to remember what this election is about. Exhausted by the car alarm of politics, one wishes only for peace and quiet.

Then along comes a moment that feels real and good and true — Memorial Day in Oxford, a tiny town at the end of the road on the Eastern Shore of Maryland, where about 125 friends, neighbors and strangers gathered in a tight circle around a small stone monument in the town park. Umbrellas aloft, all listened intently as a retired Navy captain, an Episcopal priest and the town’s police chief took turns reading the names of those who have fallen since last Memorial Day.

As the bugler played taps, veterans in our small group saluted while others covered their hearts. It was a tender moment of reverence — all too rare and nothing like the cacophony of the public square.

As the priest said a final prayer and the color guard passed, I felt profoundly sad, not just for those who died and their families but for the nation known as the United States of America. I’m not alone. People write. Friends call to talk about what’s to come. Sitting on my stoop in Washington, a neighborhood gathering spot on any given afternoon, my fellow “stoopers” speak more seriously than they used to. Life is less fun as the future seems more ominous.

Democracy, freedom, civilization — it all hangs by a thread. America was always just an idea, a dream founded in the faith that men were capable of great good. It was a belief made real by an implausible convention of brilliant minds and the enduring courage of generations who fought and died. For what?

Surely, not this.

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