SWAT team members are posted next to a ShadowHawk drone in Texas. Worried about violations of civil liberties, at least 19 states are considering limits on how the unmanned craft can be used. (Vanguard Defense Industries via Associated Press)

SWAT team members are posted next to a ShadowHawk drone in Texas. Worried about violations of civil liberties, at least 19 states are considering limits on how the unmanned craft can be used. (Vanguard Defense Industries via Associated Press)