Vanguard Defense Industries

An unusual bipartisan revolt has erupted against law enforcement plans to fly more drones equipped with high-tech gear that can be used to conduct surveillance of Americans.

A combination of concerns about privacy, air traffic safety, facial recognition, cell phone tracking -- and even the possibility that in the future drones could be armed -- have suddenly placed police on the defensive.

A public outcry in Seattle last month prompted the mayor to ground the police department's nascent drone program. Oregon held a hearing this week on curbing drones, following one in Idaho last week. And on Tuesday, Rep. Ed Markey (D-Mass.) introduced a federal bill that would require law enforcement to obtain warrants before conducting drone-based aerial surveillance.

Benjamin Miller, who runs the drone program for the sheriff's office in Mesa County, Ariz., and represents the Airborne Law Enforcement Association, encountered a less-than-welcoming Senate Judiciary committee during a hearing on Wednesday.

"I think a great many of us, myself included, have very deep concerns about the government collecting information on the citizenry," said Sen. Ted Cruz (R-Texas). "And with the ease and availability of drones, I think there is a real concern that the day-to-day conduct of American citizens going about their business might be monitored, cataloged and recorded by the federal government."

Miller probably didn't do himself any favors by saying that ostensibly non-lethal weapons -- including tear gas, pepper spray, and flash-bang grenades -- might be deployed on police drones. He said, however, that arming drones with such weapons, which have been known to kill people on occasion, would probably not be very "responsible."

In October 2011, police in Montgomery County, Texas, received delivery of a ShadowHawk unmanned aerial vehicle from Vanguard Defense Industries. The ShadowHawk can be equipped with a TASER weapon system, which delivers a high-voltage electronic shock through what Vanguard calls "multi-shot XREP launching" delivered by a "patented targeting- and firing-system." Montgomery County has said, however, it's considering weaponizing its ShadowHawk with rubber bullets and tear gas instead.

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New drone-regulation laws are unnecessary, Miller said. When Americans are in public or in other places where "no reasonable expectation of privacy exists, we would be opposed to restrictions that would limit the effectiveness of this technology," Miller said. He added that police will abide by "their oaths of office to uphold the laws of this nation, to include the laws that protect the privacy of its citizens."

The problem is, however, that there may not be any laws that specificially protect the privacy of citizens from drones operated by police.

"We don't believe that there are actually any federal statutes that would provide limits on drone surveillance in the United States," said Amie Stepanovich, director of the Domestic Surveillance Project at the Electronic Privacy Information Center. "The privacy laws that do exist are very targeted [and] don't encompass the type of surveillance that drones are able to conduct."

Fueling some of the privacy concerns is that law enforcement agencies have not always been terribly forthcoming about what they're doing with either their smaller police-grade drones, or the far larger ones, like Reaper and Predator drones, that are operated by some federal agencies and were originally designed for military applications.

Homeland Security's Customs and Border Protection agency declined to answer questions from CNET earlier this month about whether cell phone direction-finding technology, specified in procurement requirements, is currently in use on its drone fleet.

Sen. Chuck Grassley (R-Iowa) said this week that he's had no success in getting answers from Attorney General Eric Holder about whether Justice Department agencies, including the FBI, the Drug Enforcement Administration, and the Bureau of Alcohol, Tobacco, Firearms, and Explosives, are using drones.

"Last June, when the attorney general appeared before the committee, I asked him whether the department was using or planning to use drones for law enforcement purposes," Grassley said. "To date, I haven't received an answer. This, even after another appearance before us this month." (A Justice Department spokeswoman did not immediately respond to questions from CNET today.)

The House of Representatives voted two weeks ago to require the Defense Department to disclose whether military drones are being operated domestically to conduct surveillance on American citizens.

Separately, Rep. Zoe Lofgren (D-Calif.) introduced legislation last month that would establish legal safeguards, and the Federal Aviation Administration recently said that it will "address privacy-related data collection" by drones.

Michael Kostelnik, the Homeland Security official who created its drone program, told Congress that the department's drone fleet would be available to "respond to emergency missions across the country," and a Predator drone was dispatched to the tiny town of Lakota, N.D. to aid local police in a dispute that started with who owned six cows. The alleged cow-nabber arrested through Predator surveillance lost a preliminary bid to dismiss the charges.

It took a high-profile Senate filibuster from libertarian-leaning senator Rand Paul (R-Ky.) to secure a response from Attorney General Holder about whether weaponized drones could be used domestically against U.S. citizens. Holder responded in a terse letter (PDF) saying that the president does not have the authority to "use a weaponized drone to kill an American not engaged in combat on American soil."

"The executive branch has been stingy with information, and that has created a vacuum that is now being filled with reactions of all kinds," Steven Aftergood, who directs the Project on Government Secrecy at the Federation of American Scientists, said at the time.