Privacy advocates fear Brett Kavanaugh would bring pro-surveillance sensibilities to the Supreme Court, as recent opinions suggest strong deference to the authorities on electronic record collection.

They say the federal appeals judge, nominated by President Trump last week to replace Justice Anthony Kennedy on the Supreme Court, could stem broadening application of the Fourth Amendment to communications records, lifestyle information, and location data generated by cellphones and Internet-connected devices.

In a well-read opinion, Kavanaugh offered an expansive view of data that the government can collect by claiming it’s needed to prevent terrorism.

In 2015, the U.S. Court of Appeals for the D.C. Circuit refused without comment to rehear a case against the National Security Agency’s dragnet collection of domestic call records. Kavanaugh attached a two-page concurrence saying the dragnet, which Congress already voted to end, was constitutional, rejecting a lower judge’s conclusion it likely violated the Fourth Amendment.

Kavanaugh wrote that the dragnet did not constitute a “search” under the Fourth Amendment, citing the third-party doctrine established by the Supreme Court's 1979 decision in Smith v. Maryland — a common perspective among judges, though one that may ultimately be revisited.

But he added that even if it was a "search," the government could take the records because it had a “special need” in preventing terrorism, overriding privacy interests.

The breadth of Kavanaugh’s “special need” concept is unclear, but the case dealt with millions of U.S. phone lines and records stored for five years. Although created to prevent terrorism, there was no evidence the database helped disrupt a terror plot, according to a 2014 report from a government watchdog agency.

"Kavanaugh went out of his way to position himself at the outer limits of executive power," said George Washington University law professor Jonathan Turley.

“Notably, it runs against the type of protective approach of recent cases like Carpenter,” Turley said, referring to a Supreme Court ruling last month requiring a warrant for authorities to collect historical cellphone location data.

In the Carpenter ruling, justices side-stepped Smith v. Maryland’, but stressed that some data from cellphones wasn’t “voluntarily” shared with companies, meaning that authorities need a warrant.

Similar analysis may expand to other forms of data-collection, and potentially to dragnet programs.

Ongoing challenges against NSA bulk collection programs include a lawsuit from the Wikimedia Foundation against “Upstream” collection from the Internet’s backbone. The U.S. Court of Appeals for the 4th Circuit found Wikimedia has standing, and the lawsuit is in discovery.

Other emerging disputes involve real-time location data acquired by authorities using cell-site simulators, and data from Internet-collected wearable and household items.

The outer limit of what Kavanaugh would allow is unclear, said Fourth Amendment scholar Orin Kerr, a law professor at George Washington University, citing the brevity of his writing. But “Kavanaugh's view was more national-security oriented than privacy oriented, certainly,” he said.

The rights of corporations may also gain from his presence on the court.

Last year, Kavanaugh wrote companies that offer Internet access have First Amendment rights to control what customers see. On net neutrality, Kavanaugh wrote in a dissent on the U.S. Court of Appeals for the D.C. Circuit that the Federal Communications Commission acted unconstitutionally by forbidding Internet providers from discriminating against traffic for profit.

Kavanaugh likened companies that offer Internet access to publishers, finding they could control traffic.

“[T]he First Amendment bars the Government from restricting the editorial discretion of Internet service providers, absent a showing that an Internet service provider possesses market power in a relevant geographic market,” he wrote, leaning on Supreme Court rulings from the 1990s contesting "must play" FCC rules requiring cable companies to carry local TV.

Kavanaugh's opinions have some advocates worried.

"Technology policy issues are going to be increasingly finding their way to the Supreme Court," said Evan Greer, deputy director of Fight for the Future, which supports regulated net neutrality and opposes mass surveillance.

"Over the next several years the court could decide whether an algorithm can be used to put you in jail, or whether you can be targeted by a drone based on what you post on social media," Greer said. "This is about more than just net neutrality and mass government surveillance. If the Senate confirms Brett Kavanaugh they will be voting for a future where technology is used to spread authoritarianism and tyranny rather than to expand democracy and free expression."