Does it violate human rights to hold children in fenced enclosures in grim facilities that are bone-chillingly cold for weeks on end? Is separating children from their parents a form of cruel and unusual punishment? When does a crisis justify the kind of treatment normally seen as inhumane?

The furious debate over migrant detention along the nation’s southwest border with Mexico has put these questions front and center in American politics. But they’re not new. The treatment of people on the margins of American life — criminals, immigrants, civilians in overseas war zones — has always proven a challenge to our democratic ideals.

Yet beginning in the 1920s, activists waged a half-century-long struggle to persuade the Supreme Court to stop abusive practices by authorities. After World War II, the United States also committed itself to the promotion of international human rights. These two signal developments have been seriously eroded, first by the excesses of the war on terrorism and now by the Trump administration’s targeting of the unwelcome and powerless, whether they are undocumented immigrants in the United States or asylum seekers. We have returned to a pattern of willful ignorance, one that allows us to avoid grappling with deeply immoral policies.

Threats to our safety, perceived or real, have long justified the kind of “tougher policies” that President Trump has demanded for the southern border. He may not be well versed in history, but the president is joining a long line of elected officials who found that rights and basic norms are easily jettisoned when they collide with demands for greater security. Across our history, from the Indian wars to the war on terrorism, officials were quick to call for “tougher policies” and slow to fill in the details. In 1901, President Theodore Roosevelt ordered military commanders in the Philippines to adopt “the most stern measures” to punish Filipino guerrillas; in a subsequent campaign the Marines followed orders and left a trail of devastation and death across the island of Samar. But such methods were justified as a “military necessity.”

Roosevelt rationalized the brutal treatment of alleged guerrillas by citing the need to stanch the threat to security. This kind of evasive language has repeatedly prevented us from coming to terms with acts of cruelty carried out in the name of national security. We’re seeing that pattern again.

What precisely did Trump officials mean when they announced “a tougher direction” for immigration? They certainly imply more than just the proposals for new fees and regulations reducing the numbers of asylum seekers. Are the American people ready to confront the reality of harsh security measures? Or will we retreat into euphemisms such as a “hardened” border and “zero tolerance” for migrants that covers up the reality of what is actually happening on the border?

As early as 2014, immigrants-rights advocates appealed to the Department of Homeland Security to investigate more than 100 instances of Customs and Border Patrol (CBP) agents abusing child immigrants. A quarter of the children reported physical abuse, including sexual assault, the use of stress positions and beatings. Many more suffered verbal abuse, including death threats. Since then, goaded by Trump, CBP and Immigration and Customs Enforcement (ICE) agents have applied even more extreme measures, including harsh confinement and prolonged separation of families.

We are deciding day by day whether to extend the basic protections of law and civilization to the people arriving on our border. For much of the nation’s history, the prohibition on cruelty and torture in American law rested on the premise that the fundamental decency of Americans, especially empathy for fellow citizens, would make such violations unthinkable.

But our capacity to empathize begins to fray at the margins, and we grow less certain about who, exactly, deserves protection. Those deemed undeserving, unwelcome or powerless — Native Americans, the enslaved, prison inmates and criminal suspects — have commonly suffered forms of violence and abuse that violated our national principles. Some people are inside the protection of the law, and some are cast out from it.

We’re seeing a replay of that ugly history unfold along our southern border. If the Trump administration codifies its get-tough rhetoric into harsher policies, we will see far more allegations of human rights abuses against the men and women charged with securing our border. And we probably will rationalize it by claiming that those responsible are just a few bad apples rather than reckoning with the ways cruelty has been embedded in the policy itself. Like the euphemistic language of security, this choice allows us to avoid uncomfortable questions about our moral values.

In fact, we’ve already seen this pattern. Accusations of cruelty and torture by ICE and CBP agents have been circulating for years, and they follow this well-worn pattern. Official denials are followed by investigations that almost always find limited violations by “a few bad apples,” not the kind of systemic abuse that would call our broader policies into question.

This pattern has long historical roots: When investigations of police brutality in Washington during the 1930s revealed widespread use of abusive interrogation methods, the police superintendent, whose predecessors had dismissed similar allegations for decades, only grudgingly conceded that a few officers may have gone too far in their resolve to protect the public.

By seeing violations of human rights as rare exceptions, unfortunate lapses that don’t challenge our fundamental sense of decency, Americans can avoid any real reckoning with the policies we’ve approved — which often violate our purported values. Very few of the officers and soldiers responsible for the My Lai Massacre in Vietnam in 1968 and none of the architects of the George W. Bush administration’s “enhanced interrogation” policies have faced legal consequences. Even Jon Burge, a notorious ringleader of lawless police in Chicago during the 1970s and 1980s, was convicted of perjury for lying to police investigators rather than torturing countless suspects.

Focusing on bad apples has long allowed us to excuse morally bankrupt policies. We need to realize that human rights abuses on the southern border aren’t spurred by immoral actors in ICE or CBP, but rather because of a political leadership that can’t or won’t come up with humane immigration policies.

Congress needs to do its job and exercise scrupulous oversight of Trump’s immigration policies. But the real solution to our border crisis is to demand that all elected officials, from local sheriffs to senators, responsibly address immigration and human rights. Trump declared that he wants immigration to be a key campaign issue in 2020. His opponents should accept that challenge. We must shine a spotlight on cruel and illegal policies that undermine our national ideals and find the wisdom and the courage to do better.