CHICAGO >> Is the huge classified ad site an abettor of sexual trafficking and exploitation, or a beacon of free expression? Does it generate crime, or help solve it?

To many who’ve seen the seemingly endless and unadulterated invitations for sex on Backpage.com — promising to fulfill "Your Kinkiest Dreams," among other things — the answer to such questions is pretty clear-cut, especially since some of the escorts in the ads have been found to be minors forced into the sex trade.

"How is it possibly legal to help pimps sell kids? Since when is that legal in the United States of America?" asked Erik Bauer, an attorney in Tacoma, Washington, who is representing four young women in a lawsuit against Backpage. They are seeking damages from the site because their convicted traffickers used it to sell them to johns when they were 7th and 9th graders.

Unlike Craigslist, another major site, which gave in to persistent calls to drop its escort ads nearly five years ago, Backpage has defied the pressure. Since then, it has become the dominant online player in the adult ad industry in the United States and, increasingly, internationally.

Invoking both the First Amendment and the federal Communications Decency Act, Backpage general counsel Liz McDougall argues that the site and its employees do not write the ads but merely provide the space to do so.

And she goes further, claiming the oft-vilified Backpage is actually one of the good guys, working with law enforcement behind the scenes to help save victims and put traffickers behind bars.

When it comes to fighting sex trafficking, "I am a true believer that this is one of the most valuable tools there is on the Internet," said McDougall, a first amendment lawyer based in Los Angeles.

It is a claim that drives many critics wild, though not everyone. At least one anti-trafficking group has been willing to work with Backpage to rescue young women and has accepted substantial donations from the site.

And as many law enforcement officials point a finger of blame at Backpage and tangle with the site in court, others on the front lines of the fight against sex trafficking say Backpage can be an ally — even if sometimes uncomfortably so.

"I don’t feel like demonizing them is the appropriate response. I feel like we should be working with them and focusing on … things that could make a difference," said Sgt. Grant Snyder, the lead detective on the human trafficking team at the Minneapolis Police Department.

Like officials in other big-city departments, he confirms that he regularly gets information directly from Backpage that helps convict traffickers and rescue victims. "It helps us recover more victims. It helps us recover them sooner."

On the other side, there’s Thomas Dart, sheriff of Cook County, Illinois, which includes Chicago.

Dart has complained about Backpage for years and last month dealt a major blow by helping convince Visa and Mastercard to stop providing payment services for the site’s adult ads, which American Express had already done earlier this year.

"Whoever it is that’s facilitating these horrible crimes, we can’t just sit back and say, ‘Well, that’s OK. I guess it’s a business model,’" Dart said.

He spoke to The Associated Press the day before a judge issued a restraining order, preventing him from making further comment until a Backpage lawsuit against him is resolved. The next hearing in the case is scheduled Aug. 20 in federal court in Chicago, where a judge is expected to rule on whether Dart needs to retract his statements to the credit card companies.

Backpage is arguing that, as a public figure who used official letterhead and language such as "cease and desist" when contacting the credit card companies, Dart infringed upon the free speech of Backpage users and, McDougall says, interfered with a law-abiding company’s ability to do e-commerce.

"He has endeavored to shut down an entire Internet speech platform because there’s certain speech on there that he doesn’t like," McDougall said. "If government officials, especially any local sheriff, was able to do that, it would be devastating to free speech on the Internet."

Though his spokesman, Benjamin Breit, says the sheriff only wanted Visa and Mastercard to stop allowing payments for adult ads, the companies dropped service to the entire site last month. American Express still provides payment services for other ads, including in the employment section.

While awaiting a ruling, Backpage — a Delaware corporation with headquarters in Dallas and a parent corporation in Amsterdam — has continued to operate, allowing users to place free basic ads in its adult category. The company is seeking lost revenue from the sheriff’s department.

Before this latest development, Dart estimated that the company, in April alone, published more than 1.4 million adult services ads and made at least $9 million.

Some of those ads are posted by sex workers such as Grace Marie, a dominatrix in Los Angeles who tweeted recently to complain about Dart’s campaign.

"As a system, Backpage is decidedly anti-pimp. It creates a direct and easy-to-use interface between providers and clients," Grace Marie said when contacted by the AP. She uses her first and middle names in her work and asked that her last name not be used in the story, citing safety concerns and the fact that her work is not legal. "Sex workers can advertise from the safety of their home, and they don’t have to rely on a third party for protection or promotion."

The bigger concern among law enforcement, however, is sex trafficking.

Victims are not always, as many think, women or children smuggled in from foreign countries to work as sex slaves. Police say sex trafficking is as much a homegrown crime — with victims who could be from just around the corner, controlled by pimps with drugs and alcohol or threats.

Its critics claim that Backpage helps promote this illegal trade, and some lawyers have sued to try to hold the site accountable.

Bauer, the attorney in Washington state, is awaiting a ruling from his state’s Supreme Court on whether his lawsuit on behalf of the trafficked teens can go forward. Another suit, filed on behalf of victims in Massachusetts, recently failed after a federal judge ruled that, under the Communications Decency Act, Backpage can’t be held responsible for content its users create.

Backpage is making the same agrument in the Washington case. However, Bauer said he’s taking a different tack — that Backpage is not simply "some innocent, blank bulletin board" but that it helps its users develop the sex ads.

"The pimps are all doing jail time, but their main facilitator, Backpage.com, is not," Bauer said.

On Sheriff Dart’s turf, recent trafficking arrests also have led to convictions of pimps whoe used Backpage. They include these cases:

– Tyrelle and Myrelle Lockett from Dolton, Illinois, were first convicted of trafficking two young women, ages 17 and 18, when the brothers were still in high school. Most recently, they’ve been serving a four-year sentence in federal prison for forcing another teen into the sex trade after bringing her from Minnesota to Illinois.

– Guillaume Thomas was convicted this year of involuntary sexual servitude of a minor after police found a juvenile at a motel in Lansing, Illinois, whom Thomas forced into prostitution.

– Elizabeth Roeder of Milwaukee is serving a six-year sentence for trafficking yet another juvenile at a motel in River Grove, Illinois.

In the latter two cases, Backpage ads led police to the motels where the teens, who were eventually taken to a rescue program, were being held.

In fact, since 2009, Cook County sheriff’s officers have made more than 800 arrests either by using information from Backpage ads or posting fake ads to lure johns, a common tactic in police departments.

Dart has concluded, though, that any help from Backpage is not worth what he sees as an endless tide of sex trafficking on the site.

When posting ads, he said, traffickers often use stolen credit cards and IDs, or generic prepaid credit cards as well as prepaid cellphones that are difficult to trace.

Dart, whose staff had met twice with McDougall to try to find a way to work together, said Backpage’s refusal to stop accepting generic prepaid cards was a big reason he went directly to the credit card companies.

Meeting with law enforcement is not unusual. McDougall has taken part in training for officers with the New York City and Los Angeles police departments, as well as internationally with Interpol. She said she cooperates with federal attorneys and other prosecutors to provide information and answer questions.

Dart, however, said he was further disappointed by what he said was a lack of specifics on how Backpage effectively monitors ads for trafficking. McDougall maintains that she shared details about Backpage’s four-step monitoring process, using computer filters, two employee checks and then spot checks to flag potential child sex trafficking ads. Suspicious ads, she said, are sent to the National Center for Missing & Exploited Children, and, in some instances, directly to police.

In March, for instance, police in Panama City, Florida, arrested two Illinois men — Dashawn Taylor and Kevin Dante Finley — and charged them with procuring a minor for prostitution. Police found the two men with a 16-year-old girl at a Panama City hotel after Backpage reported an ad with a photo of an underage girl to NCMEC’s sexual exploitation CyberTipline.

Still, NCMEC’s top online analysis expert said Backpage could do more.

"Mere reporting has fallen short .," said Staca Shehan, executive director of the center’s case analysis division, which oversees the organization’s child sex trafficking team. "We think that a responsible company would take all available measures to address child sexual exploitation."

Bradley Myles, CEO of the anti-trafficking group Polaris, also has described Backpage’s methods as "unchecked abuse."

McDougall said the site’s staff keeps suspected trafficking ads live until law enforcement tells them it’s OK to take them down, so as not to tip off pimps that they’re being investigated. She said they also do their best to remove ads tied to a particular email address and phone numbers, but that identifying people through credit cards was one of the most reliable tools. Age, she said, is particularly tricky to verify online.

"There’s no question that kids are going to slip through on some of those ads," said Lois Lee. She is the founder and director of Children of the Night, a residential program in Van Nuys, California, for young people, ages 11 to 17, who are attempting to leave prostitution.

While some anti-trafficking organizations have shunned Backpage, she has been working with the site since 2011, when she asked McDougall to visit her facility.

By the end of this year, Backpage will have donated $700,000 to the program since 2012 — all of it, Lee said, used to feed, clothe and educate young women who come to her, often by way of police departments across the country.

Lee said she initiated the contact with Backpage after vice detectives told her that information the company provided was helping get trafficked teens and adults to safety, as in the Florida case. The site also has agreed to run public service ads for a Children of the Night rescue hotline next to its escort ads.

"You have to deal with people that are actually in the mix," Lee said, explaining why she works with Backpage — just as she works with vice officers and drug-addicted victims fleeing abuse. "None of it is pretty."

During an interview with the AP via videoconference, teenage girls from Children of the Night sat around a table telling about their lives as victims of sex trafficking.

They ranged in age from 14 to 17 and came from across the country, from California, Washington and Nevada, all the way to Wisconsin and New York. They were lured into "the life," as they call it, by people who offered them a place to stay and a meal — then fancy clothes and eventually drugs and alcohol.

Often, they said, their "dates" with strangers were arranged on Backpage. Still, they said they didn’t think stopping Backpage would solve the problem. "Even if there weren’t Backpage, there’d be something else you could post on," said one 15-year-old from Spokane, Washington, who got involved in a sex trafficking ring run by gangs and said she was beaten.

Police agreed that there will always be other online sites for ads. Snyder, in Minneapolis, said he recently tried to get information on a suspected trafficker from a Canadian ad site that declined to cooperate.

"We can’t shut down the Internet. So are we better off having a strategy that turns the very tools that (criminals) use to traffic back on them?" Snyder asked. "I think we are. "

Even so, Dart, in his interview before the restraining order was imposed, said he hoped the credit card companies would withhold their payment services from the "next entity" that allows escort ads, as they have Backpage.

"We’re never going to eliminate this," the sheriff said. "But what we can do is to make it more difficult for the criminals who are involved with this — and make it easier for us to catch them."