Expulsions on the scale the Trump administration envisions are hardly unknown to history. Even modern countries, within memory, have sought to rid themselves of entire populations. It tends neither to turn out well nor reflect well on the expelling country. Two hundred thousand people may not sound like a huge number on a historic scale. But the population of San Salvador, El Salvador’s capital, is only 280,000. Money sent home by Salvadorans living abroad, most in the United States, where protected status conveys work authorization, amounts to 17 percent of the country’s gross domestic product, according to the country’s central bank. The destabilizing effect of cutting off this flow of capital is obvious.

The potential economic effects in this country are less obvious, but real. Contrary to what President Trump might think, the Salvadoran community is highly productive. According to the Center for Migration Studies, a think tank in New York affiliated with a Catholic group, the Congregation of the Missionaries of St. Charles, 88 percent of Salvadorans participate in the labor force (the construction and food service industries are their biggest employers), compared with 63 percent of Americans as a whole. They pay taxes and own homes. Since individuals with protected status are ineligible for welfare and other social benefits, this is a group that contributes to the country while taking little.

And the human cost of expelling them is nearly unbearable. More than half have been in this country for at least 20 years. During that time they have become parents of some 200,000 United States-born citizens. Ten percent of the protected-status Salvadorans are married to legal residents. What exactly does the Trump administration think should become of these families? “Not even a dog would leave their babies behind,” Elmer Pena, an Indianapolis homeowner who has worked for the same company there for 18 years, said to USA Today. His children, United States citizens, are 10, 8 and 6 years old.

So some number, probably a large number, of the affected individuals won’t leave. They will be forced underground, turned from a life of productive labor to a life in the shadows where, in the age of Trump, immigration agents — who chafed under the Obama administration’s enforcement priorities and whose union supported and cheered Donald Trump’s election — feel free to go so far as to stake out a hospital to pick up and detain an undocumented 10-year-old girl after emergency surgery. (It came to light last week that the anti-abortion zealots in charge of caring for unaccompanied minors who enter the country illegally were refusing for a fourth time, despite court orders to the contrary in earlier cases, to permit a pregnant teenager to exercise her right to an abortion. They yielded only when faced with another lawsuit.)

While temporary status is sometimes granted because of war or extreme political turmoil, the Bush administration added El Salvador to the list after a natural disaster, not a man-made one. But a man-made disaster did befall this unfortunate country not so long ago, in the form of United States support for a murderous right-wing dictatorship that the administration of President Ronald Reagan regarded as a bulwark against Communism. The 12-year-long civil war there, during which the United States-supported military killed hundreds in the village of El Mozote, was a bloody final front in the Cold War, outlasting the Berlin Wall before it ended in 1992. The scars have faded, but memories are still fresh; an investigation into what happened in El Mozote was reopened in 2016 by a court in El Salvador at the request of three human rights groups.