It’s wise to put up walls to create and reinforce boundaries. There are emotional walls designed to create safety, and social media walls that say, “Keep out!” in subtle or not so subtle ways. Physical walls create barriers to entry. I recently visited what’s left of the Berlin Wall. Now I see walls everywhere. Walls of rooms create beautiful ways to keep people close. Some walls selectively allow people in and out, and some are clearly barriers to entry.

Walls of all kinds make strong statements. Many of them define a need for personal space.

At this time in our history, as soon as we see the word, "wall", there's only one wall we think of, and that's the wall Trump promises to build to create border security with Mexico.

Perhaps the last time a wall so dominated world thought was when the Chinese built the Great Wall — a 13,000 mile fortification made of stone, brick, tamped earth, wood, and other materials — built to protect the Chinese states and empires against the raids and invasions of nomadic groups. Apart from defense and controlling immigration and emigration, the Great Wall included border controls to impose duties on goods transported along the Silk Road.

Is the Great Wall Trump’s inspiration? The wall as he described it during the campaign,

“would not be one continuous barrier along the entire stretch of more than 1,900 miles of land between the United States and Mexico, but rather sections of a wall. Natural barriers and border patrol people stationed in certain parts of the Southwest would provide security between the sections.”

And building the wall would be easy, Mr. Trump said.

“I’m a builder. The construction would not be as complicated as building a 95-story high-rise. And I would have Mexico pay for it. Believe me. The estimated cost of the wall would be $4 billion to $8 billion. It would be 35 feet to 45 feet high, with a big, fat beautiful door right in the middle, which would be for people to enter the country legally.”

President Trump’s description is so specific that we can visualize the wall — I think that will be his downfall. All politicians make promises, but none are as easily visualized as Trump’s wall. And yes as a builder he has “wall credibility.”

If I promised to build a wall, you’d have good reason to doubt me, but here we are — walled in by a president’s promise.

We visualize the wall, but will it be realized?