The U.S. Supreme Court on Monday appeared divided over whether to allow a group of lawyers, journalists and human rights researchers the ability to challenge a government surveillance tool that critics say intercepts protected communications and violates privacy and speech rights.

Plaintiffs in Clapper v. Amnesty International, represented in the Supreme Court by Jameel Jaffer, deputy legal director at the American Civil Liberties Union, want an injunction to block enforcement of a controversial provision that Congress adopted in 2008 as part of the Foreign Intelligence Surveillance Act. The statute gave the authorities new and sweeping powers to intercept and review phone and e-mail communication of non-U.S. citizens living abroad.

The U.S. Justice Department has said it considers the provision a “vitally important national security statute.” Critics of the law describe it as “dragnet” surveillance untethered from individualized suspicion or probable cause. The government asked the high court to review an appellate court decision that revived the litigation.

Lawyers, journalists and others who routinely communicate with sources and clients in foreign countries—people who are potentially targets of national security probes—argue the government’s “vacuum-cleaner-style” surveillance has minimal oversight and lacks forceful safeguards. The challengers contend they must alter they conduct—for instance, speaking in generalities on the phone—to protect against the threat of government surveillance.

The question in the Supreme Court, however, isn’t about the merits of the surveillance law but, rather, whether the plaintiffs even have legal standing to pursue a case in the first place. Justices on the court’s liberal wing appeared skeptical at the government’s insistence that the challengers have no right to sue because they’ve failed to show a concrete injury rooted in the surveillance initiative.

Solicitor General Donald Verrilli Jr. argued the plaintiffs’ alleged harms flow from what he described as a “cascade of speculation.”

The challengers, he argued, only offer speculation about the scope of government conduct. The plaintiffs do not know, for instance, whether the foreign residents with whom they are communicating are targets of national security surveillance, Verrilli said.

“They have to speculate that whatever surveillance occurs will occur under this authority, as opposed to other forms of lawful authority that they do not challenge,” Verrilli said during one exchange with Justice Stephen Breyer. Verrilli said, earlier, that the challengers also must speculate about the U.S. intelligence priorities and objectives.

Justice Ruth Bader Ginsburg told Verrilli at one point that the challengers can never know how the government is specifically enforcing the surveillance provision. “I mean, I know you emphasize the speculative nature of this claim, but it’s not speculative if the government being given this authority by Congress is going to use it,” Ginsburg said.

The surveillance statute, Justice Anthony Kennedy said, poses a potential ethical dilemma for a lawyer who wants to communicate with a particular client who is overseas. Kennedy called the ethics problem a “substantial” one. “I think the lawyer would engage in malpractice if he talked on the telephone with some of these clients, given this statute,” Kennedy said.

Verrilli insisted that the law has a robust accountability structure that includes “targeting requirements, minimization requirements, certification by the highest level.” He sought to convince the high court that “this is no free-ranging authority at all.”

The ACLU’s Jaffer argued that the challengers do have the legal foothold to proceed with their case because of the “substantial risk” that the government will eavesdrop on protected communication.

“The government’s insistence that plaintiffs cannot establish standing without proving the certainty of surveillance is at bottom not a standing argument but a bid for a kind of immunity,” Jaffer wrote in the challengers’ merits brief. “This is because its proposed standard is one that neither plaintiffs nor anyone else will ever be able to meet—not because the surveillance they fear will never take place but because they will be unaware of it when it does.”

Chief Justice John Roberts Jr. said a would-be plaintiff’s future harm—in order to acquire standing to sue—must be “impending,” not just based on a substantial risk of an injury down the road. “There is obviously a vast difference between the two,” Roberts said.

Roberts also told Jaffer that the challengers’ concern about government monitoring of communication is present is “every area of practice” of the law.

“If you’re representing someone who is being prosecuted, you don’t send an e-mail saying, ‘You know, the government hasn’t yet asked where you threw the gun, and we’ve got to be prepared to answer questions on that because, as you know, that’s a real probable,’” Roberts said. “I mean, you don’t send messages like that through the e-mails or just talk casually over the phone either.”

Responding to Roberts, Jaffer said the statute in question is focused specifically on the government’s collection of foreign intelligence information. The statute, Jaffer said, makes the challengers “especially concerned” about their communication with people living abroad.

If the challengers win in the Supreme Court on standing, the case could return to Judge John Koeltl of U.S. District Court for the Southern District of New York. Koeltl in 2009 dismissed the suit, rejecting the notion that the challengers’ “abstract fear” of government interception of communication creates legal standing.

“In this case, the plaintiffs’ reluctance to engage in their desired speech is self-imposed because their fear of surveillance under the FAA is an abstract and hypothetical [one],” Koeltl said in his ruling. A panel of the U.S. Court of Appeals for the Second Circuit revived the legal fight, and the full court declined to hear the case.

Mike Scarcella can be contacted at mscarcella@alm.com.