• by Wendy Davis , Staff Writer @wendyndavis, October 29, 2015

Sheriff Thomas Dart's showdown with Backpage.com could have ripple effects that go far beyond the fate of the classifieds site and its controversial adult ads.

That's according to the Center for Democracy & Technology, Electronic Frontier Foundation and Association of Alternative Newsmedia, which want a federal appeals court to rule that Dart, a sheriff in Illinois, didn't have the right to lobby credit card companies to de-fund Backpage.

Dart's tactics "have traditionally been used against distributors such as bookstores and movie theaters to suppress the dissemination of information and ideas," the groups argue in papers filed on Wednesday with the 7th Circuit Court of Appeals. They add that Dart's approach presents "a grave danger in an era of online bookstores and ad-supported platforms for individuals’ speech."

The organizations are urging the appellate court to reverse a decision issued earlier this year by U.S. District Court Judge John Tharp, Jr. in Illinois, who ruled that Cook County Sheriff Thomas Dart had a free-speech right to voice his complaints about Backpage.com to Visa and MasterCard.

Both companies said in June that they would no longer process payment for transactions on Backpage.com. That move came after Dart wrote to the companies -- on official letterhead -- and asked them to "immediately cease and desist" allowing their credit cards to be used to purchase adult services ads. Dart, like many other observers, says that Backpage's "adult" ads are actually prostitution ads.

Backpage then filed suit against Dart. The company sought an order prohibiting him from continuing with efforts to cut off the site's funding. Backpage -- which argues that it isn't responsible for crimes committed by users -- said its business was jeopardized as a result of Dart's move.

Tharp initially accepted Backpage's argument, but later rejected the company's position. Among other reasons, Tharp said that Dart was entitled to "publicly criticize the credit card companies for any connection to illegal activity, as long as he stops short of threats."

The digital rights groups say that ruling is problematic. They argue that there's a big difference between Dart expressing himself as an individual, and doing so in an official capacity.

"By improperly insulating Sheriff Dart’s threats within the protective cloak of the First Amendment, the district court has sanctioned extralegal government tactics to suppress not only an entire category of protected expression, but an entire platform dedicated to the exchange of information and ideas," they argue.

The groups also say that Dart's letters to Visa and MaterCard should be seen as threats, arguing that the letters invoke "legal and reputational risk for Visa and MasterCard," and carried "threats of future sanctions intended to coerce the credit card companies into a course of action ultimately aimed at censoring Backpage.com."

The organizations also point out that Dart's campaign could effectively censor Backpage -- although the First Amendment typically prevents government officials from censoring speech.

Their legal papers cite numerous instances when officials turned to intermediaries in hopes of cutting off support for particular Web sites. One of the most recent occurred in 2012, when lawmakers convinced Visa and MasterCard to stop processing payments to WikiLeaks, after it published classified cables. (A judge in Iceland later ordered the companies to resume processing payments for the site.)

"Government coercion of technological and financial intermediaries in order to suppress lawful speech and to shut down hosts of third-party content is a major threat to free expression in the digital age," the groups argue. "It is a particularly insidious form of government censorship, as it occurs through informal channels that circumvent due process protections and judicial oversight."

The 7th Circuit will hear arguments in the case on Nov. 13.