*Town Wall, c. 13th century, Rotenburg ob der Tauber, Bavaria, Germany*

Hadrian built one. The colony of New Amsterdam built one. Berlin built one. So did Constantinople. And Jerusalem. And possibly Jericho. Throughout history, every settlement that gave a thought to its stature and survival built a wall. Some were meant to keep people out. Some were designed to keep people in. Some, as Robert Frost noted, said they meant to do one thing even while doing the opposite. But the "beautiful wall" that Donald Trump keeps promising to build along the border between the United States and Mexico can’t be reduced to a simple purpose. Nor can it be reduced to a single part of speech. For Trump, "Wall" is both noun and verb. In both cases, they mean danger.

Tough Sell
As recently as the G20 meeting earlier this month, the President insisted that he was “absolutely” convinced that Mexico would pay for the wall, even though these days more unauthorized non-Mexicans are apprehended at the US Border than actual immigrants from Mexico. With all the other Trumpian material in their baggage train, members of the House and Senate are not exactly clamoring to finance a two thousand mile long billion dollar barrier, even one made of solar panels.

But why even bother? The walls are already up. According to the Dow Jones site MarketWatch, fewer travelers are coming to the US from international locations, and 6% fewer prospective travelers are seeking information online. This shouldn’t surprise anyone who followed the G20 meeting in Hamburg last week. The President quickly succeeded in becoming the least popular leader at the meeting. He sat alone at the conference table as the 19 other participants engaged in substantive dialogue. Trump has distressed America's allies by pulling out of the Paris climate agreement and has further offended them with his aggressively isolationist “America First” posturing. Without appearing to break a sweat, Donald Trump built a wall around himself.

The Wrong Kind of Elk
And the walling doesn’t stop there. Consider all of his proposed roll-backs . To name a few, he has taken aim at environmental regulations protecting clean air and water, at measures designed to prevent financial mayhem, at birth control, at nutrition programs for children, at health care for tens of millions of Americans and at seemingly every single thing that Barack Obama ever tried to do. Believe it or not, Rick Perry's Energy Department has ordered up a study of whether wind, solar and other forms of renewable energy pose a threat to coal, oil and natural gas. Maybe a solar wall isn't such a good idea after all, Mr. President. Meanwhile, The Onion has satirically reported that the Interior Department has requested the resignation of all the elk appointed during the Obama administration, regardless of subspecies (thanks, Jim Warren).

All of these acts of denial, withdrawal and rejection recall an ancient, archetypal legend. In an essay published in the 1960s, the Argentinian writer Jorge Luis Borges reflects on the Chinese Emperor Shih Huang Ti (pictured) who, after bringing the Six Kingdoms under his rule, began the building of what we know today as The Great Wall of China. But that’s not all he did. He also ordered that all books written before his time be burned. As Borges observes, calling for the immolation of 3,000 years of learning, in a culture that reveres its past, was a shocking act. Perhaps, Borges suggests, “the wall in space and the fire in time were magic barriers designed to halt death.” In a current idiom, that approach might resonate with a 70-year old man preoccupied with his hair-do. More pragmatically, if we take the tale at face value, it tells the story of a ruler who wanted to establish absolute control over space and time by abolishing the world outside and the world before. It's all connected.

George Orwell, whose classic 1984 is enjoying brisk sales these days, understood this all too well. The slogan of the Party in the novel is: "Who controls the past controls the future: who controls the present controls the past."

So be alert! As Sergeant Esterhaus used to say on Hill Street Blues, "Let's be careful out there."