Imagine this.

You’re a journalist covering a street protest, and the local police chief doesn’t like the photos you’re tweeting from your iPhone. One shows an officer arresting a minister. Another shows a protester surrendering as an officer chokes him. Yet another shows a teargas canister landing near a group of young people. The batons and rubber bullets come out, and …

… the chief remotely disables the journalist’s iPhone, rendering it useless.

Soon that will be within the realm of possibility in California—technically, if not legally. Last week Gov. Jerry Brown (D) signed into law a bill that requires any smartphone manufactured after June 2015 and sold in California to include a feature that can render the device inoperable, a so-called “kill switch.”

The bill was framed as an antitheft measure, developed to allow a smartphone owner to disable her device if it’s stolen. State Sen. Mark Leno (D-San Francisco), who authored the bill, said in a statement, “California has just put smartphone thieves on notice. Our efforts will effectively wipe out the incentive to steal smartphones.” 

Citing Consumer Reports, the statement said that in the US the number of victims of smartphone theft rose from 1.6 million to 3.1 million between 2012 and 2013. And the bill itself, citing the Federal Communications Commission, said smartphone theft accounts for 30-40 percent of robberies in major cities nationwide, many violent and some resulting in the loss of life.

From an anti-theft and consumer-safety standpoint, a kill switch isn’t a bad idea. In fact, it’s not even a new idea. Apple users already can download the Find My iPhone app to locate a device, track where it’s been, prevent anyone from using it, and erase personal data stored on it. Other companies provide similar services to Android and Blackberry users. 

So my concern isn’t that smartphone theft is unfit for a technical response—it’s that the California legislation leaves open the possibility that law enforcement could hit the kill switch and stop newsgathering in its tracks.

To be clear, the scenario outlined above would likely represent an illegal act by law enforcement. A subsection of the law states that any government request “to interrupt communications service utilizing [the kill switch] is subject to Section 7908 of the Public Utilities Code,” which sets standards for such requests.

The standards are decent and generally require law enforcement to obtain a court order before interrupting any communications service by any means. Under § 7908, it would be okay to proceed without a court order only if the agency could prove exigent circumstances after the fact to a judge. (Users will also be able to opt-out of the default kill switch setting, though I question whether opting-out would actually stop a law enforcement agency determined to disable a phone.)

As the Electronic Frontier Foundation pointed out in a letter opposing the California law, it should concern us—journalists especially—that the law gives government actors greater ability to disable smartphones. Recent events in Ferguson, MO, remind us that abuses and police overreach happen. And the § 7908 standards were enacted to address the controversy caused when wireless service was shut off during the 2011 BART protests. With those things in mind, EFF wrote in its letter:

[The law] is not explicit about who can activate [the] switch. And more critically, [it] will be available for others to exploit as well, including malicious actors or law enforcement. While [the law] adopts the requirements of … § 7908 to … limit the circumstances in which government … officials can activate [the switch], the fact remains that the presence of such a mechanism in every phone by default would not be available but for the existence of [the law]. In essence, [the law] mandates the technical ability to disable every phone sold in California, and … § 7908 provides the necessary legal roadmap to do the same.

The San Francisco Examiner reported that the EFF unsuccessfully lobbied to amend the law so only a smartphone’s owner could hit the kill switch, and Wired reported that Apple, Blackberry, Google, and other firms initially opposed the law but dropped their opposition after its effective date was delayed. Meanwhile the CTIA, a trade group for the wireless telecommunications industry, opposed the law.

Notably, California wasn’t the first to pass a kill switch measure—that distinction goes to Minnesota, and Nevada is drafting one now, too. But it’s expected that California’s will be highly influential because the state is home to so many tech firms, and tends to lead other states in tech regulation.

Jonathan Peters is CJR's press freedom correspondent. An attorney, he is an assistant professor of journalism at the University of Kansas, where he teaches and researches media law and policy, with an affiliate research position exploring big data and Internet governance in the KU Information & Telecommunication Technology Center. Peters has blogged on free expression for the Harvard Law & Policy Review, and he has written on legal issues for Esquire, The Atlantic, Slate, The Nation, Wired, and PBS. Follow him on Twitter @jonathanwpeters.