Nearly 300 people agree to the five months, after being hustled through mass hearings, with one lawyer for 17 people, each having about 30 minutes of consultation per client. The plea deal is a brutal legal vise, but the immigrants accept it as the quickest way back to their spouses and children, hundreds of whom are cowering in a Catholic church, afraid to leave and not knowing how they will survive. The workers are scattered to federal lockups around the country. Many families still do not know where they are. The plant’s owners walk freely.

This is enforcement run amok. As Julia Preston reported in The Times, the once-silent workers of Agriprocessors now tell of a host of abusive practices, of rampant injuries and of exhausted children as young as 13 wielding knives on the killing floor. A young man said in an affidavit that he started at 16, in 17-hour shifts, six days a week. “I was very sad, and I felt like I was a slave.”

Instead of receiving merciful treatment as defendants who also are victims, the workers have been branded as the kind of predator who steals identities to empty bank accounts. Accounts from Postville suggest that that’s not remotely what they were. “Most of the clients we interviewed did not even know what a Social Security number was or what purpose it served,” said Erik Camayd-Freixas, a Spanish-language interpreter for many of the workers. “This worker simply had the papers filled out for him at the plant, since he could not read or write Spanish, let alone English.”

The harsh prosecution at Postville is an odd and cruel shift for the Bush administration, which for years had voiced compassion for exploited workers and insisted that immigration had to be fixed comprehensively or not at all.

Now it has abandoned mercy and proportionality. It has devised new and harsher traps, as in Postville, to prosecute the weak and the poor. It has increased the fear and desperation of workers who are irresistible to bottom-feeding businesses precisely because they are fearful and desperate. By treating illegal low-wage workers as a de facto criminal class, the government is trying to inflate the menace they pose to a level that justifies its rabid efforts to capture and punish them. That is a fraudulent exercise, and a national disgrace.