Peel away the billionaire braggadocio, set aside the insults and bile, and Donald Trump is running for president on a promise to build a protective wall around America’s white working class. Most famously he is promising to build a physical wall on the Mexican border – which he will somehow persuade the Mexicans to pay for – to protect American workers from immigrants bent on stealing their jobs. But he is also promising to build trade walls by renegotiating free trade agreements so workers in China and elsewhere can’t undercut American workers. And he is promising to wall us off from the world diplomatically so American blood and treasure will no longer be spent defending our allies in Asia and Europe.

This is the core message Trump hopes to ride to the Oval Office: If we build a big, beautiful wall around Fortress America, we can sustain ourselves without the help of the rest of the world.

Let us ignore for a moment all the practical reasons why this make no sense. Forget that, whoever ends up paying for it, no wall can keep out desperate, hungry people who already tunnel miles underground and cross searing deserts for a better life in America. Forget, too, that with more than 11 million illegal aliens living in this country, some of them for decades, we are never going to be able to send them all home. And forget that free trade deals, while they do send many jobs overseas, also benefit Americans by reducing the cost of goods we all buy.

Forget all that. Trump is wrong because, while he, along with Democratic firebrand Bernie Sanders, have tapped into the deep pain being felt by America’s working class, they are misdiagnosing its root cause. Companies have always cut costs by shopping around for the cheapest workers. Bankers and corporate executives have always taken their profits first and absorbed their losses only after everyone else has suffered. Politicians have always sided, often corruptly, with whoever holds the most money and power.

What is different today, and what is ailing America’s working and lower-middle classes, is the way machines have fundamentally reshaped the work undereducated workers do. Advances in technology are gradually draining the skill and human judgement from every kind of working-class labor, from weaving a bolt of cloth to frying a hamburger, giving companies free rein to transfer once reasonably well-paid skilled and semi-skilled American jobs to unskilled foreign workers, both here and abroad. At the same time, advances in communications and transportation have enabled companies to build truly global supply chains, opening the way for them to shop the world for the cheapest and least powerful workers to do the job.

Together these forces, the de-skilling of human labor and the shrinking of the world of commerce, are helping corporations grow ever larger and more powerful and shifting ever more earning power from the assembly line to the executive suite. The more money and power the elite amasses, the more they can game the system to amass more money and power, until you’re left with a situation like ours, where a typical CEO makes 330 times more than the average worker and the top 1 percent of Americans hold 40 percent of the country’s wealth.

The growing gap between rich and poor in America is morally appalling and politically unsustainable, but many of the forces driving the disparities are systemic and irreversible. No wall we can build will stop the seepage of jobs overseas in a fully globalized and technologically mobile world, and a shift to a democratic socialist model that worked for highly homogenous northern European countries in the middle part of the last century is unlikely to work in our own fractious, racially diverse country facing 21st century problems. Whether we like it or not, we are stuck with the world we have made, along with the deep problems it is causing us, and we have no choice but to innovate our way out of it.

The thing is, we did it once before. In the 1930s, when mechanization finally pushed America’s small farmers and sharecroppers out of the fields and into factories, we saw a profound shift in the role of government in people’s lives. When poor people could no longer feed themselves from their own plot of land, however meager, governments had to step in to find new ways to feed the hungry and care for the sick and elderly. The Soviet Union responded to this crisis with Communism. Central Europe responded with Nazism. America responded with the New Deal. Then, 10 years later, we had a war to see which system worked best.