Ever since his days on the election campaign trail, U.S. President Donald Trump has assured voters of his intentions to build a wall along the U.S. border with Mexico. He reiterated this promise during the 2019 State of the Union Address, and then declared a state of emergency soon after in order to access funding that Congress had rejected. It is now included on Trump’s 2020 re-election campaign website as part of a broader agenda to curb immigration.

Opponents of Trump’s border wall have dismissed the project as politically self-serving and financially frivolous. But arguments against the border wall have primarily focused on the cost to U.S. taxpayers, suggesting economics as the most compelling framework through which a border wall project could be shot down.

Others have focused on the environmental impact a border wall might have on the habitats and migration flows of North American wildlife.

It seems that many have avoided discussions of the moral issues raised by the border project and its long-lasting consequences for human civilization. By contrast, Trump doesn’t rely on fiscal responsibility to justify his project, stressing his administration’s “moral duty to create an immigration system that protects the lives and jobs of [. . .] citizens.”

But it is the moral costs of the border wall that should raise the greatest concern for the world at large. In my study on the lasting impact of border walls on society, I examined centuries of history and politics to uncover the consequences of the ancient walls surrounding Damascus on present-day Syrian society.

Those Roman walls, built around the 3rd century A.D., were intended to protect the city and its inhabitants from invaders. They surrounded the city, allowing inhabitants to enter and exit at seven points, the famous seven gates of Damascus. In 749 A.D., Abu Abbas al-Saffah destroyed the walls during his overthrow of the Umayyad Caliphate, leaving only a small portion that extended from the Bab Touma gate to the Bab al-Salam gate.

Today, long after they were destroyed, the Roman walls continue to have an effect on the structure of Syrian society, dictating marriages, business networks, and many other elements of socioeconomic status. There are websites that list the family names of notables who historically resided “within” the city walls, bestowing an enduring distinction on generations of Syrians born with last names like the one my mother bore.