Some things simply need to be together. Human civilization really took off when we discovered that bronze could do much more than either copper or tin by themselves. Today, neither computers nor software can do much apart from one another. And a wall separating certain celebrities from the scandal sheets would bring the rapid demise of both.
The same is true of human communities. The wall dividing Germany, and the continuing heartache it produced, dominated the country's consciousness for two generations. The North Korean dictatorship has shamelessly manipulated families' anguish at the division by imposing extortionate conditions on visits; those feelings are so strong that the South acquiesces. It is difficult to imagine that we are contemplating a new wall to further separate closely interdependent families, communities and economies on the two sides of the U.S.-Mexico border.
But human communities are not the only ones the border wall would fracture. The border wall that President Donald Trump has threatened to shut down the government to build would be an environmental disaster that would split closely connected animal communities as it does human ones.
Some 700 species now divide their time between this country and Mexico, perhaps finding food or water on one side but returning to the other to mate and raise their young. The fences and walls we have across more than a third of that border have already caused major harm to these animals. Extending the wall, as Congress may this fall, would both destroy sensitive habitat and prevent cross-border travel on which many animals depend. It also would block waterways and cause more flooding, which is the last thing Texas needs now.
One of the many interdependencies we have with Mexico that never penetrates the current debate involves wildlife refuges. For an animal population to be healthy and stable, it must be large enough to avoid the genetic risks that inbreeding causes. And with each animal requiring a certain amount of land to find food and appropriate shelter, a refuge must be of a certain size to maintain viable populations. Neither we nor Mexico have sufficient gray wolves in the border area to survive, but combined there just might be enough.
The Santa Ana National Wildlife Refuge in extreme south Texas is quite small. Its connection with similar habitats in Mexico, however, allows it to maintain an incredible variety of rare and beautiful wildlife. More than 400 species of birds shelter in the refuge as do half of all North American species of butterflies. If the border wall is built, it will bisect the Santa Ana Refuge, cutting part of it off from Mexico. It also would deny Americans access to much of the refuge, including a lovely 19th century church on the "wrong" side of the wall's path. The wall would deprive us of a national treasure while doing little to slow illegal immigration.
Mexico also provides us with precious second chances to correct our blunders in wildlife conservation. Nothing shows this more clearly than the story of the jaguar. This majestic beast, the only close relative of lions and tigers in the New World, once ranged throughout the southwestern U.S. The loss of habitat and exaggerated, now-discredited fears of predators caused them to become extinct in this country. A population still exists in Sonora, however, and occasionally some of its members cross the border to explore their species' old territory. Working with the Mexican government, the U.S. Fish and Wildlife Service has protected a corridor for jaguars to travel north and suitable habitat for them when they arrive. A border wall would slice right through that area, destroying any chance of getting wild jaguars back.
Business lobbies have killed the "border adjustment tax" by pointing out how many products move back and forth across the border several times during the process of production. If only ocelots and pygmy cactus owls could hire similar lobbyists. Instead, advocates for wall-building enacted legislation in 2006 that allows sweeping waivers of environmental protections.
As climate change intensifies, many animals will seek to shift north as Mexico becomes too hot for them. If a wall blocks their way, the result will be dead wildlife in Mexico rather than healthy populations here. Welcoming this wildlife would add to our biological diversity and compensate, in a sense, for the loss of animals seeking cooler weather in Canada.
When President Ronald Reagan demanded, "Mr. Gorbachev, tear down this wall!" he captured a transcendent truth about interfering with natural connections. The Berlin Wall did not serve its purpose: The brutal, corrupt East German regime still fell. President Reagan's political heirs should not sacrifice our treasure, our economic health, our relationships with our neighbors, and the wonderful but endangered wildlife of the border region to build another futile wall.
David A. Super (das62@law,georgetown.edu) is a law professor at Georgetown University.