Do you know that your local city bus might be listening to your conversations?

Depending on where you live, the sidewalks could be recording your every step. And your lampposts and subway cars may be watching you, too.

Once a paranoid notion of science fiction, perpetual state surveillance is fast becoming the new normal. In some cases, the technology is being activated without the consent of the public.

When the Maryland legislature considered a bill to turn on audio recording devices inside its statewide fleet of 758 buses, it set off a fierce debate in the Senate. Delegate Melvin Stukes argued that audio surveillance is a powerful tool to help fight crime, and individuals cannot expect privacy on public transportation. Opposing him was senator James Brochin, who warned of an assault on civil liberties and the frightening potential for government abuse.

But make no mistake, this was more than a clash of two powerful state politicians. This was a struggle between two cherished American values: privacy versus security. It's a conflict that's playing out in communities all across the United States.

So far, surveillance is winning. After the Maryland legislature rejected three bills that sought to activate audio surveillance in buses across the state, the transit authority turned them on anyway, on the advice of the state attorney general.

Do citizens get any say in the matter? In a 1967 ruling, Katz v. United States, the Supreme Court affirmed that the individual right to privacy depends largely on a set of norms that are determined by society. In other words, if you have a reasonable expectation of privacy – even if you're in a public place – then you are entitled to it.

Surveys show strong and growing public support for some kinds of surveillance. An April 2013 New York Times poll shows that 78% of respondents approved the use of video cameras in public places. Terrorist incidents like Boston Marathon bombings have made the public ever more receptive to cameras in the name of fighting crime. (The poll didn't ask about audio recording.)

A recent study by the Urban Institute concludes that surveillance has a significant effect on reducing crime. Baltimore, a city with the fourth highest murder rate in the nation, has benefitted from video cameras, as have Chicago, and Washington, D.C.

Yet downsides remain. Even in the young history of audio-visual surveillance, the ACLU notes that the technology has already been abused. Members of law enforcement have used information gleaned from cameras to blackmail, spy, and harrass citizens. And if these crimes seem relatively minor now, imagine how a future J. Edgar Hoover would make use of the all-seeing eye, with its powers of voice-matching and face-recognition.

It's a worrisome prospect. Senator Brochin, who accepts video cameras while condemning audio surveillance, is quick to remind us how eavesdropping poses a threat to an open, democratic society. Citing the widespread use of covert listening devices in authoritarian countries, he remains concerned about what the future is going to look – and sound – like.

Surveillance technology has certainly become powerful, and promises to become more so. But when and whether that technonology is used – that power still remains with us.

Runs about 8:12 minutes.

Produced, shot, and edited by Todd Krainin.