Marcello Lucero was killed late Saturday night near the commuter railroad station in Patchogue, N.Y., a middle-class village in central Long Island. He was beaten and stabbed. The friend who crouched beside him in a parking lot as he lay dying, soaked in blood, said Mr. Lucero, who was 37, had come to the United States 16 years ago from Ecuador.

The police arrested seven teenage boys, who they said had driven into the village from out of town looking for Latinos to beat up. The police said the mob cornered Mr. Lucero and another man, who escaped and later identified the suspects to the police. A prosecutor at the arraignment on Monday quoted the young men as having said: “Let’s go find some Mexicans.” They have pleaded not guilty.

The county executive, Steve Levy, quickly issued a news release denouncing this latest apparent hate crime in Suffolk County. That should be the first and least of the actions he and other leaders take.

A possible lynching in a New York suburb should be more than enough to force this country to acknowledge the bitter chill that has overcome Latinos in these days of rage against illegal immigration.

The atmosphere began to darken when Republican politicians decided a few years ago to exploit immigration as a wedge issue. They drafted harsh legislation to criminalize the undocumented. They cheered as vigilantes streamed to the border to confront the concocted crisis of Spanish-speaking workers sneaking in to steal jobs and spread diseases. Cable personalities and radio talk-show hosts latched on to the issue. Years of effort in Congress to assemble a responsible overhaul of the immigration system failed repeatedly. Its opponents wanted only to demonize and punish the Latino workers on which the country had come to depend.

A campaign of raids and deportations, led by federal agents with help from state and local posses, has become so pervasive that nearly 1 in 10 Latinos, including citizens and legal immigrants, have told of being stopped and asked about their immigration status, according to the Pew Hispanic Center. Now that the economy is in free fall, the possibility of scapegoating is deepening Hispanic anxiety.

It is not yet clear how closely connected Mr. Lucero’s murder is to this broad wave of xenophobia. But there is both a message and opportunity here for officials like Mr. Levy, an immigration hard-liner whose relations with his rapidly growing Latino immigrant constituency have been strained by past crises and confrontations.

Deadly violence represents the worst fear that immigrants deal with every day, but it is not the only one. It must be every leader’s task to move beyond easy outrage and take on the difficult job of understanding and defending a community so vulnerable to sudden outbreaks of hostility and terror.