Maricopa, which includes Phoenix, is home to more than half of Arizona's 6.2 million people. It is also the domain of Sheriff Joe Arpaio, who is determined to make life miserable for undocumented immigrants. Trouble is, "Sheriff Joe," as he is universally known, isn't too particular about how he and his men identify undocumented immigrants, or whether they also harass legal immigrants such as Mr. Ortega, or, for that matter, American citizens who happen to be Hispanic. "We know how to determine whether these guys are undocumented," Mr. Arpaio told the Chicago Tribune recently, "the way the situation looks, how they are dressed, where they are coming from."

Mr. Ortega had been in the United States for barely three weeks last September when Mr. Arpaio's deputies stopped the vehicle he was riding in. Despite showing the officers his documents, Mr. Ortega says he was handcuffed, treated roughly, jailed and finally turned over to federal immigration officials, who promptly released him. During the nine hours Mr. Ortega spent in custody, no one offered him a translator, or any explanation for his treatment, or food or water. Nor did anyone advise him of his Miranda rights. Little wonder Mr. Ortega is now afraid to be seen in public.

His experience is included in a class-action lawsuit filed last week in federal district court in Arizona against Mr. Arpaio, his office and Maricopa County. The complaint recounts similar episodes, including one involving Velia Meraz and Manuel Nieto, U.S. citizens who say they were ordered from their car at gunpoint, handcuffed and menaced by sheriff's deputies who seemed to take offense that the pair were listening to music on a Spanish-language radio station.

The lawsuit lays out a pattern of alleged racial profiling by the sheriff's office, which by all appearances systematically seizes the flimsiest of pretexts — failing to use a turn signal and the like — to check the papers of people of Hispanic descent. By equating race with immigration status, the sheriff's office has made moving around Maricopa County risky and at times terrifying for many Latinos, immigrant and native alike.

Sheriff Joe likes to refer to his blatantly unconstitutional campaign of harassment as "crime suppression sweeps." These "sweeps" have been denounced not only by Latino groups, which consider them overtly racist, but also by the mayor of Phoenix, who has asked the Justice Department to investigate, and by Gov. Janet Napolitano, who has withdrawn state funding from the sheriff's office.

The sheriff loves describing himself as a tough guy and delights in humiliating prisoners by, among other things, making them wear pink underwear and swelter in open-air camps. He has gotten away with it — even won reelection — thanks to his colorful public persona and an electorate rattled by the demographic changes caused by immigration, legal and undocumented. He denies allegations of racial profiling even as his deputies practice something that looks awfully like it. It's high time for federal authorities, or courts, to step in to halt what has become a travesty of justice in Arizona.