Programs like the Pentagon's balloon experiment "pose a grave threat to basic human rights, freedom of expression, and civil liberties," Fight for the Future Deputy Director Evan Greer told Common Dreams. "These programs are not about stopping violence, they're about social control."

The data the balloons' sensors will record is similar to information the military has previously gathered using planes and is sometimes referred to as "combat Tivo," according to Arthur Holland Michel of the Center for the Study of the Drone at Bard College.

"When an event happens somewhere in the surveilled area, you can potentially rewind the tape to see exactly what occurred, and rewind even further to see who was involved and where they came from," Michel told The Guardian.

The use of wide-area surveillance by the military opens up huge possibilities for privacy violations and for the targeting of any American who may be engaged in activity that the government deems dangerous in the present or the future, the ACLU said.

"Even in tests, they're still collecting a lot of data on Americans: who's driving to the union house, the church, the mosque, the Alzheimer's clinic," Jay Stanley, senior policy analyst for the organization, told The Guardian. "We should not go down the road of allowing this to be used in the United States and it's disturbing to hear that these tests are being carried out, by the military no less."

The military's project is just the latest example of a massive surveillance infrastructure that the government is creating, sometimes with the help of powerful private companies, Greer told Common Dreams.

"From police partnerships with Amazon's Ring doorbells to these privately contracted spying balloons," she said, "a dystopian surveillance state is being built in plain sight, by government agencies with authoritarian dreams and corporations willing to trample our rights to turn a profit."