In his 43-year career as a federal judge, Jack B. Weinstein has come to be identified by his efforts to combat what he calls “;the unnecessary cruelty of the law.”; His most recent crusade is particularly striking because of the beneficiary: a man who has amassed a vast collection of child pornography.

Weinstein, who sits in the U.S. District Court in Brooklyn, N.Y., has twice thrown out convictions that would have ensured that the man spend at least five years behind bars. He has pledged to break protocol and inform the next jury about the mandatory prison sentence that the charges carry. And he recently declared that the man, who is awaiting a new trial, did not need an electronic ankle bracelet because he posed “;no risk to society.”;

There is little public sympathy for collectors of child pornography. Yet across the country, an increasing number of federal judges have come to their defense, criticizing changes to sentencing laws that have effectively quadrupled their average prison term over the past decade.

Last week, the U.S. Court of Appeals for the 2nd Circuit vacated a 20-year child pornography sentence by ruling that the sentencing guidelines for such cases, “;unless applied with great care, can lead to unreasonable sentences.”; The decision noted that the recommended sentences for looking at pictures of children being sexually abused sometimes eclipse those for actually sexually abusing a child.

Weinstein has gone to extraordinary lengths to challenge the strict punishments, issuing a series of rulings that directly attack the mandatory five-year prison sentence faced by defendants charged with receiving child pornography.

“;I don't approve of child pornography, obviously,”; he said in an interview this week. But, he also said, he does not believe that those who view the images—as opposed to producing or selling them—present a threat to children.

“;We're destroying lives unnecessarily,”; he said. “;At the most, they should be receiving treatment and supervision.”;

The man that he has spent three years trying to save from a long incarceration is Pietro Polizzi, a married father of five who collected more than 5,000 graphic pictures of children. If prosecuted in a New York state court, he would have faced a maximum prison sentence of four years. Instead, in federal court, he faced a minimum of five years and a recommended sentence of 11 to 14 years. Because of Weinstein's intervention, he remains free as he awaits another trial.

“;I don't see Judge Weinstein as a judge,”; Polizzi said during an interview as tears rolled down his face. “;I see him as my father. He helps people. He doesn't destroy lives the way the prosecutor has. He's the one who is going to set me free from the court.”;

The child pornography industry has flourished through the Internet, with the number of federal cases growing from fewer than 100 annually to more than 1,600 last year. As the number grew, Congress increased the recommended prison terms, and established a mandatory minimum sentence of five years for anyone convicted of receiving child pornography. According to the federal defenders' office, the average sentence was 91 months in 2007, up from 21 months a decade before.

But the tough penalties have chafed many judges, echoing previous battles over drug cases. Last year, judges imposed sentences below the recommended range in more than half of all child pornography cases.

“;What has caused concern in courts across the nation is that we have a lot of relatively law-abiding individuals sitting in the basement downloading the wrong kind of dirty pictures facing not just prison sentences but incredibly long prison sentences,”; said Douglas A. Berman, a professor at Moritz College of Law, who studies sentencing issues.

In one recent case, James L. Graham, a U.S. District Court judge in Ohio, sentenced a 67-year-old man who had suffered a stroke to a single day in prison, along with restrictions on computer use and registration as a sex offender. As part of a deal with prosecutors, the man had pleaded guilty to possession of child pornography, which carries no mandatory sentence.

“;When you have to sit there on the bench and look at someone like my stroke victim and say, 'I have to send this man to prison for six years,' it just doesn't feel right,”; he explained in an interview. “;It's not right.”;

Child advocates like Ernie Allen, the president of the National Center for Missing and Exploited Children, are upset by such thinking. “;Real children are harmed in the production of these images and these same children are harmed every time these images are downloaded and viewed,”; he said.

At 88, Weinstein is one of the longest serving members of the federal bench. Supporters praise his taking unusual actions in pursuit of his notions of justice, like for a time refusing to handle drug cases out of opposition to mandatory minimums. Critics say that in the process, he disregards the law.

(On Thursday, he made headlines by refusing to dismiss a lawsuit by a public school teacher removed from the classroom for allowing students to use vulgarities during a lesson on HIV. He ruled that she appeared to have followed the spirit of a state syllabus that directed that students be encouraged to use sexual terms they understood.)

“;Jack is somebody who will step out and do what he thinks is right and take his chances of being overturned by an appeals court,”; said John S. Martin, who cited his disagreement with mandatory sentences when he retired from the federal bench in Manhattan. “;He sees the injustice in these things and he tries to do something about it.”;

Both sides point to his efforts in the Polizzi case as quintessential Weinstein.

In 2005 Polizzi signed up for a child pornography website. He began obsessively stockpiling thousands of images, mostly of prepubescent girls. When FBI agents arrived with a search warrant, he led them to the two-story garage where he kept his collection behind locked doors, saying, “;The pictures of the children are upstairs.”;

Child pornography cases almost always end with guilty pleas. But when the case was assigned to Weinstein, Polizzi's lawyer recommended that he go to trial.

The lawyer used an insanity defense, claiming Polizzi had been repeatedly raped as a child and had collected the pictures not for sexual gratification, but in hopes of finding evidence of his own abuse—claims the prosecution dismissed as implausible. When the first of the images were shown in court, Polizzi collapsed and was taken to a hospital.

The jury was given the standard instruction not to consider possible punishment during deliberations. After three days, on Oct. 5, 2007, Polizzi was convicted of all 12 counts of receipt of child pornography and 11 counts of possession. Then Weinstein broke from the script with a question almost never posed in court: If the jurors had known about the minimum prison sentence, would they have voted to convict?

Five jurors spoke up against imprisonment. Two said they would have changed their votes. Weinstein tossed out the guilty verdict on the more serious receipt counts and ordered a new trial. He sentenced Polizzi to a year in prison for the possession counts, which Polizzi has served.

Weinstein declared that Polizzi had a constitutional right to have a jury know the punishment that would accompany a guilty verdict, a right he said he had violated. He pledged to inform the next jury of the mandatory minimum sentence. That idea, floated by a federal judge in Manhattan several years earlier in another child pornography case but rejected on appeal, would give jurors the option of refusing to convict if the punishment seemed disproportionate, as several jurors had indicated they believed it was in Polizzi's case.

“;That was quite an unusual way of handling it,”; said Amy Baron-Evans, the national sentencing resource counsel for the federal public defenders' office. “;Usually the judges are just stuck with the mandatory minimum.”;

The Court of Appeals last year overruled Weinstein's order of a new trial but left unresolved whether it was permissible to tell the jury about the punishment. The case was remanded, and Weinstein, after consulting with other District Court judges, again ordered a new trial, though this time on different grounds. And again he pledged to inform the jury of the mandatory minimum sentences. That decision is under appeal.

In the meantime, the cases keep coming.

On Wednesday, Weinstein dealt with a man who had pleaded guilty to receipt of child pornography. He imposed the mandatory five-year minimum prison term, though unhappily.

“;This is an unnecessarily harsh and cruel sentence under the circumstances,”; he said. “;The court has no alternative under the statute. This defendant requires treatment and a stable life outside of prison. Prison will only harm him and will do nothing to protect society, since he does not constitute a risk of crime or any acting out towards children.”;

He added, “;I'm sorry, there is nothing I can do in this case.”;