As Donald Trump issued an executive order intended to single out Muslims for immigration restrictions, many Americans searched their consciences for the right way to respond to this act of discrimination by their government. “First they came for the Communists/And I did not speak out/Because I was not a Communist,” begins the famous poem by Martin Niemoller. How can we avoid making the same mistake that the Germans made who failed to stand up against the first acts of repression by the Nazi regime?

Fortunately, the New York Times Magazine publishes a column called “The Ethicist” that offers advice on complex moral questions. In the most recent column (1/25/17), “The Ethicist” offers some advice that’s relevant to the Trump era of heightened xenophobia, ethnic scapegoating and threats to civil liberties: If someone confides to you about an immigration violation, he says, you should inform against them to the government.

A reader wrote in to “The Ethicist” to ask what they should do about an acquaintance who admitted to them that she had married a US citizen only in order get US citizenship. “Do I have an ethical obligation to speak out about marriage fraud when it is used to gain US citizenship?” the reader asked.

No, but it would be a good thing to do, was the response of

It is the nature of the nation-state arrangement that states have a right to regulate who crosses their borders. You may disagree with one feature or another of our system, but over all it is fairer than many others. And if someone abuses it by the sort of fraud you have described, they are not only breaking the law, they are jumping a queue that millions of other people have formed by applying properly and then waiting their turn. Given that you’re clearly not the only person who has the relevant information, and given the diffuse nature of the harm, you’re not obligated to report what you know. But provided you are morally certain about your conclusion, it would be a good thing if you did. US Immigration and Customs Enforcement has a website where you may report anonymously. (Filing false information is a crime.) It would be up to them to confirm what you say.

Presumably such advice would also apply to the estimated 11 million undocumented immigrants living in the United States whom Trump has threatened to deport. Has your neighbor admitted to you that they don’t have a green card? Homeland Security has a website where you can anonymously report them!

The New York Times can publish an updated version of the Niemoller poem: “First they came for the immigrants—and I said people should secretly turn them into the government.”

Jim Naureckas is the editor of FAIR.org. You can find him on Twitter at @JNaureckas.

You can send a message to the New York Times at letters@nytimes.com, or write to public editor Liz Spayd at public@nytimes.com (Twitter:@NYTimes or @SpaydL). Please remember that respectful communication is the most effective.