Perhaps the best political news of the Trump era has been the emergence of sanctuary cities — city governments valuing the presence of immigrants and standing for the protection of their right to live without fear — and their defiance of this country’s current manifestation of legal racism.

“How dare you vilify members of our community by trying to frighten the American public into thinking that all undocumented residents are dangerous criminals? . . . How dare you distort the reality about declining violent crime rates in a diverse, sanctuary city like Oakland to advance a racist agenda?”

So said Libby Schaaf, the mayor of Oakland, Calif., last month, in response Attorney General Jeff Sessions’ outrage that she had tweeted a warning that Immigration and Customs Enforcement agents — the ICE men — were preparing to make a massive sweep through Northern California.

ICE, a branch of the Department of Homeland Security, was created in 2003, “a direct product of the post-Sept. 11 panic culture,” as Sean McElwee put it in The Nation. Its establishment reframed immigration as a national security issue, which is to say, an exploitable source of national fear. We must protect ourselves from the illegals! The agency’s mission, particularly under Donald Trump, appears to be the dehumanization of people of color born outside the United States. It has the moral resonance of the Klan, or maybe the Brownshirts.

In the wake of Schaaf’s defiance of Trump and Sessions, the San Jose Mercury News published a fascinating letter from a man whose grandparents lived in Berlin when Hitler was in power. His grandmother was Jewish.

“A Berlin police officer was a friend and, risking his own life, would call them and warn them of any planned Gestapo raids,” he wrote. “We owe our lives to this man — he was a hero!

“I see parallels in today’s America. ICE is instilling fear in the immigrant community, going after otherwise law-abiding, hard-working people whose only crime is wanting a better life.”

Mayor Schaaf, in alerting Oakland residents of the coming ICE raids, “has the same moral fiber and courage as the Berlin police officer,” he wrote.

The time, as McElwee notes, has come to defund — to abolish — ICE: not just the agency itself, but to “abolish the function” of ICE, which is to keep immigrant communities in a state of terror.

“The agency talks about, and treats, human beings like they’re animals,” he writes. “They scoop up people in their apartments or their workplaces and take them miles away from their spouses and children.”

Indeed, the time has come to abolish the presence of an official “other”: a targeted group of people who have been legally defined in dehumanizing terminology, e.g., “criminal aliens.” This is domestic war, the sole purpose of which is the maintenance of a top-down, authoritarian social order — which, of course, is what much of the Trump base would prefer.

Jonathan Blitzer, writing last summer in the New Yorker, described his communication, initially off the record, with an ICE employee who was growing increasingly alarmed at what was happening to the agency. Eventually, he gave Blitzer permission to publish his observations.

“During the campaign, many rank-and-file agents publicly cheered Trump’s pledge to deport more immigrants, and, since Inauguration Day, the Administration has explicitly encouraged them to pursue the undocumented as aggressively as possible,” Blitzer writes, describing what the agent called an unleashing of contempt among many of the ICE guys for the immigrant community.

Whatever the agents’ private opinions were, ICE itself had a standard of integrity, but that’s no longer the case. “Now people are bringing their own opinions into work,” the agent said.

This is the alliance I fear most: between private racists and legal authority.

“The chilling effect,” Delphine Schrank wrote recently in The Guardian, “carries a whiff of life in a police state, under authoritarian or semi-authoritarian rule, where security forces strike unpredictably, rarely with just cause, and most often with inhuman efficiency.”

How far will this go? When will the words of Martin Niemoller become relevant? The German Lutheran minister famously uttered, upon his release from prison at the end of World War II: “First they came for the Communists, and I didn’t speak up because I wasn’t a Communist. Then they came for the trade unionists, and I didn’t speak up because I wasn’t a trade unionist. Then they came for the Jews, and I didn’t speak up because I wasn’t a Jew. Then they came for me, and no one was left to speak for me.”

First they came for the immigrants . . .

Racism continues to regroup around an ever-shifting other. This is world — certainly it’s American — history. Fortunately, it’s only part of our history. The same awareness and intelligence that birthed the civil rights movement is driving the phenomenon of sanctuary cities. A welcoming attitude makes everyone safer.