During the lead-up to the presidential election I felt paralyzed by the fear of what might happen. Now that Donald Trump will actually become president, it is more important than ever to speak out for what is right. And that means arguing for open borders instead of building higher walls.

I have often asked myself idly, when my mind runs away with itself, what I would have done during the time of slavery in the United States, during the days of the underground railroad. Would I have sheltered the runaway slave, helped her on her way to the North, to freedom? Or would I have left to others the dangerous, illegal, yet indisputably moral work of providing safe passage to fugitive slaves, denounced slavery with my words but not my actions? I hope I would have opened my home to those fugitives from injustice, not just spoken empty words against slavery while I lounged in the shelter of my white home.

For some time, I have felt that the path of migrants from Central America and Mexico to the United States is the underground railroad of our time. Men and women who can no longer bear the conditions in which they live—the low wages, the long hours, sometimes the violence—make the difficult decision to grab whatever they can carry on their backs and run, in the dark of night, for the North, el norte, the land where they hear they can live freely. These migrants ride a network of actual freight trains known as la bestia, the beast, toward the north, where perhaps they can make better money, find a better job, send for their families, not have to fear for their lives. The journey is dangerous. They may not make it. They may get caught by la migra and sent back to their low-wage jobs, their impoverished homes, or their deaths amid gang violence. But the risk is worth it for the possibilities that await.

I have helped migrants on today’s underground railroad—given food, clothes, first aid, friendship, even a cell phone. I spent a summer in Nogales, Sonora, Mexico, aiding migrants on their way to the north (and those who had been deported from there). But just to help people come north is not enough. The journey is not over once migrants reach U.S. soil.

Even once they reach the United States, manage to settle down, hopefully get a job, today’s undocumented immigrants are not completely safe. They are still treated as second-class citizens—or rather, not citizens at all. Congress holds plenary power over immigration, which means that Congress can apply laws to noncitizens—undocumented immigrants—that cannot constitutionally be legally applied to citizens. Thus, ironically, although migrants may seek greater freedom in el norte, their position can actually become more limited when they arrive in the United States, for they do not receive the same protections as U.S. citizens. Today’s undocumented migrants, having broken the law by entering and thus remaining in a limbo, “illegal” status, can be incarcerated indefinitely in detention centers, forcibly removed from the nation, and refused the rights given to American citizens. Like runaway slaves in the North, who could be caught by a fugitive slave catcher at any time and shipped back to their former owners in the South, undocumented immigrants who are caught by the Border Patrol can be deported at any time, regardless of how long they have lived in the United States or whether they have committed any actual crime. While deportation is justified on the grounds that undocumented immigrants broke the law in coming to the U.S., we must question the basis of very laws they have broken.

Defenders of restrictive border policy and immigration law may remind us that migrants are free within their own countries to work and move as they please, just as U.S. citizens are in our own country. Therefore, limiting the right to work for a fair wage or the right to government protection to U.S. citizens and denying such rights to undocumented immigrants is not unfair; they have those rights in their own country. Yet why should we take it for granted that people born in a nation where the minimum wage is approximately $3.54 a day (73.04 in MXN) should not be allowed to move to a country where the national hourly minimum wage is more than that? If I, a U.S. citizen, have a right to make a living wage, then someone born in Mexico or Honduras should have that right as well. If I, a U.S. citizen, can travel freely to another nation, then people in those nations should have the right to travel to my country as well. If we as Americans truly believe that all people have certain inalienable rights and that all people are created equal, then we need to end a system of border enforcement that provides certain individuals—citizens, and wealthy people who can afford to pay for expensive visas and meet the income requirements for work or travel visas—the right to movement and, thus, the right to self-determination, while denying that self-determination to people who are not born in the U.S.

The border is not an unchanging, God-given reality. The border is a man-made creation that has been moved multiple times in U.S. history. Just as slavery was an artificial division based on race that was designed to legally exclude certain people from self-determination in order to keep a captive labor class for the wealthy white planters, international borders are in the words of border scholar Reece Jones “artificial lines drawn on maps to exclude other people [noncitizens] from access to resources and the right to move.” By relying on an arbitrary border to define who has a legal right to enter, to work, and to live in the U.S., American citizens can keep wages high for citizens and legal workers and low for undocumented workers. They can constantly hold the threat of deportation over undocumented workers within the U.S. in order to keep labor costs down. Because undocumented immigrants are noncitizens who have “broken the law,” we can justify denying them citizenship and thus denying them equal rights.

Is this so different than the economic system of slavery? The American economy has always depended on low-paid (or unpaid), imported, and racialized labor in sectors such as agriculture, construction, and domestic service. In this labor market, some workers—the free whites, or the citizens—benefit from the system and advance socioeconomically, while others—the black slaves, or the noncitizens—are systematically forced into low- or nonpaying, undesirable jobs. In antebellum America, many domestic workers and farmworkers, at least in the South, were African American slaves. Today, many domestic workers and agricultural laborers across the nation are unauthorized immigrant workers from Latin America. Because these individuals are unlawfully present “aliens,” employers feel free to exploit such workers without fear that the laborers will report this exploitation or seek better working conditions. If the workers do complain, the migra can send them back to Central American or Mexico, where they will be forced to labor for even lower wages, in lower standards of living, and may be at higher risk of political or gang violence. Legally, they do not have the right to work or the right to even reside within the United States that citizens do. Everything they do can be criminalized; their very presence is considered an illegal act.

Thus today, as in the era of slavery, the U.S. relies on a racialized labor force that is legally denied the rights of full U.S. citizens. Just as in antebellum America, a legal system based on an arbitrary characteristic of birth—once skin color, now location—is used to protect the economic interests of citizens at the expense of another group.

Today’s system can be justified, as noted above, by recalling that undocumented immigrants do have rights within their own countries. They do not begin as slaves, and I do not suggest that their position is indistinguishable from that of slaves. There are differences. But we cannot congratulate ourselves on abolishing slavery and yet still systematically deny rights to some people based on arbitrary characteristics of birth. Rather than a national system that denies rights of freedom and self-determination to certain people based on the color of their skin, this is a continental system that denies rights of movement and self-determination to certain people based on their place of birth. Instead of being based on the national law of slavery, it is based on the international law of citizenship. Yet the result is still that some people in the U.S. do not have the same rights as others.

We can only have a truly equal society, internationally and within our own borders, if we grant the same rights to people from any nation. This means open borders. We cannot continue to enforce a policy of discrimination based on birthplace, a characteristic as arbitrary as skin color. People cannot change where they are born and more than they can change the color of their skin. But they should be allowed to move freely over the earth, the planet we all share, to seek opportunities and control their own destinies. Allowing some people, those born in wealthy nations, to travel freely, while restricting those born in undeveloped nations to places with low wages, poor working conditions, and fewer governmental protections, is fundamentally unfair. If we truly believe in “liberty and justice for all,” then liberty and justice should not be restricted to people born within our borders. The right to seek liberty and justice wherever it can be found, on any side of the border, should be everyone’s right, no matter which side they were born.