Earlier this week, the federal government announced that the Air Force might be dispatching drones to a backyard near you. The stated purpose of these spies in the sky is to assist local police to find missing persons or kidnap victims, or to chase bad guys.

If the drone operator sees you doing anything of interest (Is your fertilizer for the roses or to fuel a bomb? Is that Sudafed for your cold or your meth habit? Are you smoking in front of your kids?), the feds say they may take a picture of you and keep it. The feds predict that they will dispatch or authorize about 30,000 of these unmanned aerial vehicles across America in the next 10 years. Meanwhile, more than 300 local and state police departments are awaiting federal permission to use the drones they already have purchased—usually with federal stimulus funds.

The government is out of control.

If the police use a drone without a warrant to see who or what is in your backyard or your bedroom, or if while looking for a missing child the drone takes a picture of you in your backyard or bedroom and the government keeps the picture, its use is unnatural and unconstitutional.

I say "unnatural" because we all have a natural right to privacy; it is a fundamental right that is inherent in our humanity. All of us have times of the day and moments in our behavior when we expect that no one—least of all the government—will be watching. When the government watches us during those times, it violates our natural right to privacy. It also violates our constitutional right to privacy. The Supreme Court has held consistently that numerous clauses in the Bill of Rights keep the government at bay without a warrant.

Even when we don't have an expectation of privacy, we do have a right to be left alone. But merely watching us in public isn't enough for the police, as many street corner cameras are equipped with listening devices and tiny megaphones. We can expect that these devices will soon bark commands: "Put down that BlackBerry." "Look to your right before crossing." "Don't kiss her; a car is coming." Actually, Big Brother is coming, and he's not smiling.

Big Brother is watching from the skies, as well as the streets. This started when the Department of Defense decided to offer help to police—and they are prepared to accept. Never mind that the military may not lawfully operate within our borders, except in the case of rebellion, and then only when publicly authorized by the president. Never mind that the military may not lawfully be used for law enforcement, except in the case of disaster, and then only when publicly authorized by the president. And never mind that this use of drones by the Air Force was not the result of legislation debated and enacted by Congress, but was done under the authority of the president alone.

Add to all this the use of drones to kill people. President Obama has argued that he can use drones to kill Americans overseas, whose deaths he believes will keep us all safer, without any constitutional due process whatsoever. His attorney general has argued that the president's careful consideration of each target and the narrow use of deadly drones are an adequate substitute for due process. Of course, no court has ever ruled that way. The president's national security adviser has argued that the use of drones is humane since they are "surgical" and only kill their targets. Of course, that's not true, but it misses the point. Without a declaration of war, the president can't lawfully kill anyone, no matter how humane his killing.

How long will it be before the Air Force and the police adopt the unconstitutional arguments of the president's wrongheaded advisers and use the drones not only to spy but also to kill Americans in America?

The whole reason we have a Bill of Rights is to assure that tyranny does not happen here, to guarantee that the government to which we have supposedly consented will leave us alone. Do you think the government accepts that? Would you feel safe with a drone in your backyard? Would you feel like you were in America?

Andrew P. Napolitano, a former judge of the Superior Court of New Jersey, is the senior judicial analyst at Fox News Channel. Judge Napolitano has written six books on the U.S. Constitution. The most recent is "It Is Dangerous To Be Right When the Government Is Wrong: The Case for Personal Freedom."