It has become commonplace enough to merit its very own list in the culture's rankings obsession: Alongside the Top 10 movies of 2008 and Top 10 songs, the Huffington Post, a wildly popular online publication, brings you its "Top 5 Police Brutality Videos," their very own picks of cops behaving badly, captured by now-ubiquitous cellphone cameras.

In order, they include a New York City officer toppling a speeding cyclist into a pole; another NYPD officer beating a suspect repeatedly by the roadside; a swarm of Philadelphia cops dragging people out of a car and kicking and pounding them to the ground; a University of Florida student Tasered by police; and, in perhaps a moment of comic vindictiveness at Huffington, a video of a cop accidentally Tasering himself.

Weeding out a Top 5 – however insincere – is no small task. It has become its own genre: Go to YouTube and search "police brutality," and almost 18,000 results come back. Entire YouTube channels, like Copwatchers, distill incidents to dense concentration.

More are added to the rapidly growing archive every day, including, just this week, the brutal beating of a 15-year-old girl in custody with the Seattle Police Department, whose main affront to the officers in question appeared to be childishly – and harmlessly – kicking her shoe in their direction.

For law enforcement, the rapid transformation of every cellphone customer into potential documentary filmmaker – virtually every new cellphone has some video capability – can be seen as a prophecy of 1968's Democratic National Convention in Chicago fulfilled, and then some: "The whole world is watching," protesters chanted then, as hordes of passive resisters were beaten, wrestled and thrown into the backs of police wagons.

The mantra was that, in the age of TV, there was no escape from the camera's eye – in massive public demonstrations, at least. Updated for 2009, the whole world isn't just watching anymore – they're recording, too.

In Canada, that fact has crystallized in recent weeks in Vancouver, where RCMP officer Kwesi Millington has been pressed on the stand to explain the circumstances that led him to repeatedly Taser Robert Dziekanski, a just-arrived Polish immigrant who was behaving erratically at the Vancouver airport in October of 2007.

Dziekanski died from the repeated shocks, five in total; a nearby bystander captured the incident on his cellphone.

Millington, pressed by the inquiry to give his account, found it repeatedly contradicted by the video itself, a circumstance that Peter Biro, a Toronto lawyer who has represented clients who have sued the Toronto Police Service for mistreatment, finds not at all surprising.

"A police officer's testimony in any incident where that officer is alleged to have caused harm to a civilian is inherently unreliable," says Biro, a partner at the Toronto firm WeirFoulds.

Biro suggests a measure taken to what he describes as a logical extreme: All officers should have all interactions with civilians videotaped, "and in the event where it's not practical or possible, the onus would be on the officers in question to demonstrate, justifiably, why."

In the YouTube era, a surfeit of police brutality videos instantly accessible online – a huge number of beatings, and occasional, sensational shootings has cast a growing shadow over police behaviour everywhere.

As a result, notions like Biro's rankle police services everywhere.

Los Angeles is the place where you might trace the origin of this species, the Rodney King highway beating video, captured in 1991 by a bystander's camera. Today, allegations – and videos – of excessive force by police have become commonplace. In 2006, a video of a 24-year-old suspect William Cardenas, being punched in the face by LAPD officers, led to an FBI probe of brutality throughout the force.

As a result, the LAPD moved last year to install cameras in all squad cars. In an anonymous column published in the Los Angeles Times, an officer argued vehemently against it, suggesting that the constant surveillance would discourage officers from actively doing their jobs for fear of reprisal.

Dave Wilson, president of the Toronto Police Association, cautions against an over-reliance on video in law enforcement as well.

"Video shouldn't be used to replace proper supervision in the workplace," said Wilson, who called Biro's proposal "ludicrous."

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The Toronto force has faced a call for cameras in cruisers as well, most recently following the 2002 beating of Said Jama Jama, then 21, at a Tim Hortons. The footage, shot by Ottawa tourists, shows the officer punching Jama Jama repeatedly in the face. Notes taken by officers at the scene said Jama Jama struck at officers; none mentioned Jama Jama had been punched.

"Video can be useful, but video may only capture a portion of events," Wilson said. "Ultimately, you have to prioritize: Do you want to spend money on more police officers on the street, or on policing the officers you already have? Because you can't have both."

For Biro, the circumstance is nowhere near so complex. "Ultimately, (recording all police activity) protects them as much as it exposes them," he says. "When we say exposure, what we're really talking about is transparency ... If we're truly committed to the rule of law, what are we afraid of here?"