In just the last year, camera phones have captured the deaths of Eric Garner in New York, Antonio Zambrano-Montes in Washington State, Charly Keunang on Skid Row in Los Angeles, and Walter Scott in South Carolina. All were killed by police officers. And now there is Freddie Gray: after being dragged to the back of a police van, he died a week later from injuries sustained before reaching the police station. The grisly scene was recorded by several bystanders and has spawned widespread protests across Baltimore.

These images, though captured on camera phones, have sparked widespread demands for more video surveillance operated by law enforcement. In the wake of Garner’s death, for instance, city, state, and federal lawmakers aggressively pursued legislation for police body cameras. Following the video of Scott’s death, the head of the Police Executive Research Forum, an independent research organization, even confirmed that “the big push for body cameras has been driven in part by the sense that citizens have their phones and can record.”

But body cameras and camera phones are constrained by different policies and laws. The former continue to seize the imagination of judges, legislators, and the public even though they are mired in unresolved policy disputes. Camera phones, by contrast, are in the hands of citizens and are restricted by fewer laws. As a result, they have proven to be more effective in capturing and sharing footage of violent policing practices with the public.

This past December, the White House proposed a $75 million plan to purchase 50,000 body cameras, which would be doled out to municipal police departments by matching 50 percent of their camera purchases over a three-year period. A December poll from USA Today/Pew Research Center indicated that 87 percent of Americans support the technology. And as early as last August, around 154,000 signatures were collected on a petition to make the extensive request for “all state, county, and local police, to wear a camera.”

Body and dashboard cameras are meant to promote accountability and reduce uses of force. Small preliminary studies, such as oft-cited ones done in Rialto, California and Mesa, Arizona, have shown promise. But state legislatures continue to wrangle over procedures for archiving footage and ensuring its reliable release to the public. Also at issue are the details of mandates for turning cameras on, for how long, and under what conditions.

As of this month, at least fifteen states have introduced bills to restrict or bar the public from gaining access to footage. The Kansas Senate voted 40-0 in March to exempt body camera videos from the state’s open records act, and this week, the Missouri House of Representatives voted to approve a similar bill. But the provisions vary widely by state: some ensure that persons filmed can gain access to footage, whereas others—citing concerns about the costs of responding to public information requests and, above all, privacy—afford that right only to those who obtain a court order.

Video evidence furnished by camera phones is already serving to balance the relations of power.

Undecided battles over civil rights and the accessibility of information are only part of the problem. In cities from Denver to New Orleans, independent and court-appointed monitors are finding that body cameras, even where formally implemented, have not been rolling for the majority of citizen-officer interactions involving the use of force.

In one incident last September, an officer in Saratoga Springs failed to record an encounter that resulted in the shooting of a twenty-two-year-old black man. The police department had yet to implement official policies for using the cameras; the Utah County attorney simply exonerated both officers involved. There have also been incidents where an officer deliberately turned off a camera. In St. Louis last April, a squad car camera captured footage of a swarm of police beating a man on the ground. An officer calls out, “Hold up, hold up, y’all. Everybody hold up. It’s red right now, so if you’re worried about cameras, just wait.” She then walks over to the car and turns the camera off.

Some preliminary studies have found that body cameras have reduced the frequency with which force is used and the number of complaints against officers, but these reports are fairly inconclusive. The technology, which has not been studied systematically, is still plagued by insufficient regulation and the near-routine failure of law enforcement to employ it consistently.

The camera phone, by comparison, is currently more capable of sharing images of brutal policing with the public and of deterring violence at the scene.

While body cameras are angled away from police officers, citizens can use camera phones to face and film functionaries of the state. A phone’s Internet connection also sets it apart as a tool for counter-surveillance: footage can be captured and put online instantaneously (especially with new apps such as Cop Watch Video Recorder) without having to pass through an opaque, prolonged process to reach the public. In some ways, camera phones are primed for building public consensus. Their images can spread across social media and are not likely to be delayed or blocked by government censors. Also, with metadata, each snapshot generates a multifaceted digital trace, enabling images to be plotted on maps and time scales. This contextual information can provide vital exculpatory or incriminating evidence in criminal cases.

A number of present laws even work to the benefit of camera phone users. The Supreme Court ruled unanimously in Riley v. California (2014) that police need a warrant to search a cell phone. And last year, the American Civil Liberties Union asserted that capturing videos or photographs of things in plain view in public spaces—including “federal buildings, transportation facilities, and police and other government officials carrying out their duties”—is a “constitutional right.”

There are, however, some restrictions in place regarding camera phone use. Legislation such as the Video Voyeurism Prevention Act of 2004—implemented at a time when lawmakers were anxious to contend with early camera phone technology—was designed to protect privacy by prohibiting the capture of “an image of a private area of an individual without their consent.” (Law enforcement activity is exempt from this interdiction.)

But what makes the technology remarkable is that it has democratized the production of visual evidence. Any one of the two billion people currently carrying a camera-equipped smartphone is capable of gathering compelling evidentiary material on the fly. These images have radically extended the visual field on which cases are adjudicated—often providing multiple points of perspective into isolated incidents.

Besides its evidentiary power, the camera phone has also afforded a distinct mode of bearing witness. To wield one’s phone is to say: “The world is watching. You will be held accountable for what you are doing.” Ramsey Orta, the man who captured Garner’s death on his phone, was attuned to this power of the technology. In an interview, he said, “I already knew for my safety just to pull out the camera because I can’t intervene.”

In the courtroom, video evidence furnished by camera phones is already serving to balance the relations of power. It gives citizens a more equitable way to contend with the authority of the state and can offer exculpatory evidence on behalf of the otherwise defenseless. Some of this evidence is being produced by “cop-watch” organizations—in states such as New York, California, Texas, and Louisiana—which gather and train groups of camera phone users with the explicit aim of deterring or de-escalating police violence and of providing evidence for judicial proceedings. In June, a seventeen-year-old resident of Sunset Park, Brooklyn, facing fifteen years in prison, was not indicted on a second-degree felony assault charge precisely because of a video supplied to the defendant’s lawyer by a man affiliated with a cop-watch team in Brooklyn.

Camera phones are important alternatives to body cameras, but they are no panacea. One risk is that users will snap away indiscriminately, policing their own surroundings with a heightened level of suspicion without considering privacy concerns or failing to maintain a rigorous commitment to the necessity of reading images critically.

All visual evidence admits various interpretations—as highlighted by the failure to indict the officer who killed Garner, despite the compelling footage. The work of seeing, of bearing witness, does not end with the production of an image, but only begins with it; to interpret what we see, we inevitably draw on information outside the frame. And we cannot unequivocally gauge intention from filmed micro-movements of the body, such as those used to claim that Garner, and others like Rodney King, resisted arrest. These cases—along with many others involving black males, who are disproportionately gunned down by police—show how racism can saturate the visual field. It was a perverse “feat of interpretation,” Judith Butler has reminded us, that King’s battered black body could be read as a source of imminent threat to the police officers beating him.

But despite the fact that evidentiary images are subject to interpretive manipulation and can only do a small part of the legwork in the judicial process, we should not lose sight of their potential. When body cameras are deployed haphazardly by law enforcement and constrained by poor policy, they fail the public they are intended to serve. In our current political moment, camera phones provide individuals and groups with a simple but powerful means of protecting citizens against an increasingly militarized police force.