A nation’s border is nothing in and of itself. It’s just an inanimate line on a map, in the dirt, on a riverbank. It has no philosophy, personality, feelings or meaning – beyond what people on either side attribute to it.

Unfortunately, thanks to Donnie Trump’s xenophobic demagoguery in this presidential election, America finds itself in a destructive border war – not with Mexico, but with itself. He’s demanding that our southwestern border with Mexico be turned into a hostile barrier of national, cultural and racial separation that will physically scream at Latino people: “Keep out!” This isn’t conjecture – you can see it for yourself, for about a third of that 2,000-mile frontier has already been desecrated with a massive metal wall, thrusting up to 30 feet high. It scowls at Mexico with such military fortifications as pole-mounted cameras, 24-hour radar, vibration sensors, all-seeing drones, surveillance balloons and Blackhawk helicopters. It has made the border mean, yet – get this – it doesn’t work! Migrants and traffickers continually overcome it. “The wall is a fantasy,” says an Arizona border sheriff. A rancher and diehard Trump supporter dismisses Donnie’s barrier scheme as a “farce.”

Worse, the existing wall and Trump’s extension of it is a perversion of what this border has been for centuries: An enriching connection point for people on either side.

In fact, there were no sides – festivals paraded from Mexico into the U.S. and back again, businesses were totally bi-national, families extended across the so-called-line, kids played together on both sides, and the community was an organic whole.

However, Trump doesn’t concern himself with the hardship his wall extension would have on the hard-working people living along the border. He has convinced himself that hordes of rapists and drug dealers are pouring into the country in droves. Indeed, Donnie warned his supporters that if he does not win the election, we “… could have 650 million people pour in and we do nothing about it. Think of it: That’s what could happen. You triple the size of our country in one week.”

Not that there’s not an issue with border security. For example, at one part of the border, three Guatemalans waited until dusk to make their move, evading security in the remote expanse, illicitly slipping into our country. As the New York Times recently reported, “This area is a haven for smugglers and cross-border criminal organizations.” But The Donald will never see it, speak about it or even know about it, because he’s always facing south, fulminating against Mexicans, Central Americans and South Americans who cross our southern border.

Meanwhile, the scene described by the New York Times took place way up north, where rural Vermont connects to Canada. With so many of our nation’s political and security officials obsessed with the southern border, more and more criminal action – including smuggling people, drugs and weapons – has been coming across our 5,500-mile Canadian border, the longest in the world between two countries. Running from the Atlantic to the Pacific through sparsely-populated and heavily-wooded terrain, there’s often no clear demarcation of where Canada ends and the U.S. begins. Some farms, homes and businesses actually sprawl across the border.

Meanwhile, only about 2,000 agents patrol this vast stretch, and officials concede they don’t even have a good guess of how many people and how much contraband is coming across, or where.

So, Mr. Trump, shall we wall off Canada, too? And how much of our public treasury, democratic idealism and international goodwill shall we dump into the folly of militarizing both borders? By simply thinking we can wall the world out, we’ll be walling ourselves in – and that’s suicidal. Trump’s wall won’t keep undocumented migrants out, but it will lock out America’s egalitarian ideal of cross-cultural community. Rather than walling-off borders, our true national security requires that we reach across them in all directions.