It matters because along with entrusting our immigration enforcers to keep us safe, in the president’s often-tweeted phrase, we also entrust them with the responsibility of treating unauthorized immigrants not as prey but as human beings entitled to dignity, even if only minimally to due process.

Not everyone shares that view. I get that, and I’m reminded of it every time I write about immigration. Reader comments on articles about immigration, including the gripping one last week about Guadalupe García de Rayos, the Phoenix woman and mother of two American children who was abruptly deported when she dutifully showed up for her routine check-in at the local ICE office, run to “if she wasn’t illegal in the first place, she wouldn’t have been deported.”

Right. I’d like to think we’re better than that. A month ago, we were.

In what may be an early warning of what’s to come, last Friday immigration agents in Seattle took a 23-year-old Mexican into custody despite his paperwork proving that he had been granted work authorization under the deferred-deportation program, which for now remains in effect.

“It doesn’t matter, because you weren’t born in this country,” one of the immigration enforcement agents told the man, Daniel Ramírez Medina, according to a petition for habeas corpus filed on his behalf in Federal District Court in Seattle. Mr. Ramírez was brought to this country at age 7 and twice qualified for the deferral program, most recently with a renewal last May. On Tuesday, a federal magistrate judge gave the federal government until Thursday to explain the basis for the detention.

This column is usually about the Supreme Court, and this one is, too. Next Tuesday, the justices’ first day back from a monthlong recess, the court will hear an important case on whether a Border Patrol officer can be required to pay damages to the family of a Mexican boy he killed with a bullet fired across the dry bed of the Rio Grande, the international border that separated the two by only yards. The facts of the case, Hernández v. Mesa, sound highly unusual, but they aren’t; there have been 10 cross-border shootings in recent years in addition to several dozen others along the border.

This case raises important questions about the extraterritorial reach both of the Constitution and the damages remedy that is available to United States citizens whose constitutional rights are violated on American soil by a federal official. Sergio Hernández, the unarmed 15-year-old killed seven years ago by the Border Patrol agent, Jesus Mesa Jr., was not an American citizen, and the bullet reached him in Mexico. He and his friends had been playing in a dry culvert, daring each other to run up the opposite bank and touch the barbed-wire fence on the American side. The F.B.I. report initially claimed that the boys were throwing rocks at the agent, but cellphone videos showed Sergio hiding under a railroad trestle in the last minutes of his life. He was shot when he stuck his head out from his hiding place.