Republican presidential nominee Donald Trump speaks during a campaign rally on March 19 in Fountain Hills, Ariz. (Matt York/Associated Press)

Danielle Allen is a political theorist at Harvard University and a contributing columnist for The Post. Richard Ashby Wilson is the Gladstein Chair of Human Rights at the University of Connecticut School of Law.

We’ve hit the home stretch of the election. The time has come to get serious, really serious, about understanding what’s at stake with Donald Trump’s proposal to deport 5 million to 11 million undocumented immigrants and his promise that 2 million will be deported in “a matter of months” if he is elected.

In May, former homeland security secretary Michael Chertoff told the New York Times: “I can’t even begin to picture how we would deport 11 million people in a few years where we don’t have a police state, where the police can’t break down your door at will and take you away without a warrant.” He also said, “Unless you suspend the Constitution and instruct the police to behave as if we live in North Korea, it ain’t happening.”

Trump’s specific policy involves adding 5,000 Border Patrol agents, tripling the number of Immigration and Customs Enforcement deportation agents, creating a special deportation force that he has described as a military unit and deporting not merely people who have been convicted of crimes but also immigrants on visa overstays and undocumented immigrants who have been arrested, even if not convicted. He has proposed expedited procedures that would, to ensure speed, presumably require setting aside the due process protections meant to safeguard rights and minimize error.

One of the last times the world saw such a major effort at mass deportations in a developed country was in the 1990s in the former Yugoslavia. That experience is instructive.

In 1989, after the fall of the Berlin Wall and four decades of peaceful ethnic and religious relations in Yugoslavia, post-communist politicians of all three communities in Bosnia and Herzegovina (Croat, Muslim and Serb) came to power on a surge of ethno-nationalist rhetoric. Starting in 1992, they promulgated official policies such as the “Six Strategic Objectives for the Bosnian Serb People” that included the forcible removal of other groups from towns and villages, using new “crisis staffs” made up of police and civilian paramilitaries.

The process spun out of control and, in many communities, neighbors turned against neighbors, driving them out of their homes and seizing their assets. It started with a small number of activists, fewer than a few thousand people who were extreme nationalists and members of fringe parties. But as the propaganda and fear spread, the wider citizenry participated in the campaign of persecution. With the cover of official policy, civilians took it upon themselves to hasten the expulsion of members of other ethnic or religious groups. The fratricidal conflict claimed 100,000 lives. The majority of fatalities were civilians murdered in the context of mass deportations.

The Bosnian deportations grew into a systematic policy termed “ethnic cleansing.” The U.N. Security Council declared forcible removal based on ethnicity a crime against humanity in 1994. And eventually there was also accountability for political leaders who enacted deportation policies and incited their followers to hatred and violence. In March 2016, the International Criminal Tribunal for the Former Yugoslavia found former Bosnian Serb president Radovan Karadzic guilty of genocide, war crimes and crimes against humanity. The tribunal ruled that his speeches and official propaganda made a significant contribution to an overarching joint criminal enterprise to create an ethnically homogenous state of Bosnian Serbs.

The United States, of course, has its own history of mass deportations. There is the 19th-century Trail of Tears, when the U.S. government forcibly relocated members of Southeastern Native American tribes to land west of the Mississippi River. And in the 1930s and 1940s, under the pressure of the Great Depression, about 2 million Mexicans and Mexican Americans were deported; many lost their property. This was also the backdrop to the famous Zoot Suit Riots in Los Angeles in 1943, when U.S. sailors and Marines attacked Latino youths. The violence spread to San Diego and Oakland, and developed into broader racial violence that summer in Chicago, Philadelphia, Detroit, New York and Evansville, Ind. In the 1950s, the deportation of millions was attempted again with Operation Wetback; again people lost their property. Some died in the desert heat of Mexicali.

The notion that governments have learned how to conduct mass deportations in “humane and efficient” ways is ludicrous. The summary removal of millions of members of a minority ethnic or religious group from a territory has been accompanied, in nearly every historical instance, by assault, murder, crimes against humanity and, occasionally, genocide. It has involved armed roadblocks to check papers, the smashing down of doors in the night to drag people out of their homes. It has also involved unrestrained popular violence against a target population.

We might like to think that we’re above all that sort of thing, that with the right kind of training a special deportation force and beefed-up ICE units would carry out an orderly removal. But we do have in our midst the elements that have historically made mass deportations so dangerous: heated rhetoric that slurs whole minority groups (“they’re not sending their best . . . they’re rapists”); an activist minority of white nationalists; an armed minority of militiamen; and the ongoing militarization of our police forces.

Then there is the other deeper, more profound truth of the matter. Mass deportation policies give neighbors who are citizens the chance to take advantage of neighbors who are not. If due process is not going to be protected for undocumented immigrants, why would their property be protected? Or perhaps someone has a score to settle? These are the basic sorts of temptations that have, historically, led ordinary people to participate in programs that became uglier than ever expected.

Currently, we are seeing net outflows of immigrants across the Mexican border, as has been the case since 2009. In other words, we do not have an immigration crisis. But even if we did, history has shown that crisis rhetoric, coupled with a racially tinged aspiration to mass deportations, has repeatedly led to episodes that harm some severely, perhaps even mortally, and is likely to bring shame on us all.