The First Amendment has been good, really good to the online classified ads portal Backpage.com. In 2015, the US Constitution helped Backpage dodge a lawsuit from victims of sex trafficking. What's more, a federal judge invoked the First Amendment and crucified an Illinois sheriff—who labeled Backpage a "sex trafficking industry profiteer"—because the sheriff coerced Visa and Mastercard to refrain from processing payments to the site. The judge said Cook County Sheriff Thomas Dart's anti-Backpage lobbying amounted to "an informal extralegal prior restraint of speech" because Dart's actions were threatening the site's financial survival.

But the legal troubles didn't end there for Backpage, which The New York Times had labeled "the leading site for trafficking of women and girls in the United States."

Thirteen months ago, the Senate Permanent Subcommittee on Investigations, which is examining sex trafficking on the Internet, subpoenaed (PDF) Carl Ferrer, Backpage's chief executive officer. But Ferrer, citing the First Amendment, has largely refused to comply with the subpoena—which essentially demands to know everything about the company's business model and profits, including how it screens ads. That screening aspect of the subpoena are similar to the one Mississippi Attorney General Jim Hood issued to Google about its polices of policing third-party content. In July, however, Hood and Google settled their dispute about the subpoena, which read like a page from the anti-piracy playbook of the Motion Picture Association of America.

Meanwhile, in the Backpage brouhaha, one part of the 13-page Congressional subpoena requires Backpage to disclose "All documents relating to the use of a Tor browser, or any other anonymizing Internet browser on the Onion Network, to post advertisements on Backpage."

Other requirements include annual revenue, annual profits, and, among other things, "All documents" related to "Traffic directed to or from Adult Sections of Backpage's US-based websites," and "All documents relating to processing of payment and fees associated with posting advertisements."

Because of Ferrer's refusal to comply, the Senate in March unanimously approved its first contempt resolution in more than 20 years. Bolstered by horror stories of young girls saying they were sold for sex on the site, Senate lawmakers contended Backpage supports a flourishing market for sex-trafficking advertisements.

When the Senate voted for contempt, Sen. Rob Portman (R-Ohio) said the authorities had found a missing girl via a "sex advertisement" on Backpage that contained a missing child poster of the child and a topless photo of her.

"We'd certainly like to know what supposedly market-leading screening and moderation procedures missed that one," Portman said from the Senate floor.

After the unanimous vote and because of the site's resistance, the Senate asked a judge (PDF) to demand that Backpage comply.

US District Judge Rosemary Collyer sided (PDF) with the government on August 5, ruling that Backpage had "no legal or factual support" for its position that the site was protected by the First Amendment. "The Constitution authorizes Congress to investigate any issue or subject about which it can enact legislation to the extent that it 'would be materially aided by the information which the investigation was calculated to elicit,'" Judge Collyer ruled.

Backpage appealed, asking the US Court of Appeals for the District of Columbia Circuit to immediately block the order.

"The District Court was dismissive of Backpage.com’s First Amendment concerns because they did not fall into familiar areas in which this Subcommittee or other legislative bodies historically abused authority—including efforts to root out subversives, political dissidents, or civil rights agitators," Ferrer's lawyers wrote. (PDF) "But the decision overlooked the way broad and punitive investigatory demands increasingly are used in the online context to exert pressure on speakers and publishers of third-party content."

A week after Collyer's ruling, the appeals court tentatively blocked the order—without deciding the merits.

"The purpose of this administrative stay is to give the court sufficient opportunity to consider the emergency motion for stay and should not be construed in any way as a ruling on the motion," the court wrote.

The appeals panel ordered the government to reply by Friday. In its response, the government demanded that the court lift its stay. The authorities said any First Amendment rights Backpage has are secondary to the government's investigation into human trafficking on the Internet.

The Subcommittee is investigating the serious problem of human trafficking on the Internet—much of which takes place on Backpage's website—and has subpoenaed Mr. Ferrer for documents relating to Backpage's screening for illegal trafficking. It is important for the Subcommittee's investigation of Internet sex trafficking to understand what methods the leading online marketplace for sex advertisements employs to screen out illegal sex trafficking on its website. Mr. Ferrer has no First Amendment right to ignore a subpoena for documents about Backpage's business practices related to that topic. He has refused to identify his First Amendment interests except in sweeping generalities and failed even to attempt to show that any such interests outweigh important governmental interests served by the Subcommittee's investigation. Indeed, Mr. Ferrer cannot make any balancing argument because he refused to search for responsive documents or produce a privilege log describing them, claiming that the First Amendment gave him blanket immunity from having to carry out these basic duties of all subpoena respondents.

The appeals court ordered Backpage to respond by Wednesday. No hearing date has been set.