A bipartisan pair of lawmakers announced Tuesday that they would introduce legislation to require all government entities—from a federal agency to a local police department—to apply for a special license from the Justice Department before it can fly drones.

Currently, there are few privacy limitations on how individuals and the government can use drones. Last month, the Federal Aviation Administration proposed an initial set of rules for drone operators, but it only addressed safety concerns.

Republican Ted Poe of Texas and Democrat Zoe Lofgren of California will introduce their bill for the third time. The pair's first two attempts failed to make it out of committee.

Under the measure, once a public drone operator has a license, the operator can use its drones to gather information for law enforcement—but only with a warrant. That's an important step for privacy advocates, who have long pushed for legislation that would limit police drone use.

"We will definitely support this bill," said Gabe Rottman, legislative counsel for the American Civil Liberties Union, which also supported the bill when it was last introduced in 2013.

But the bill's warrant requirement is not without its caveats. Law enforcement can use drones without warrants if the drone is being flown within 25 miles of a land border, for example, or if the agency using the drone "believes an emergency situation exists" that involves organized crime or threatens national security.

"Whatever's introduced, we would want to make sure it has sufficient protection so that the emergency exception doesn't just become a giant hole that's overused," said the ACLU's Neema Giuliani.

The bill would also forbid private drone operators from spying on other individuals who have a "reasonable expectation of privacy." That means you can't use a drone to gather information or take photos or video that you'd otherwise have to trespass to obtain.

The proposed legislation covers all government use of drones, not just law enforcement. That means the Secret Service, which has been test-flying drones near the White House at night, would likely have to get special dispensation if it wanted to gather information about civilians.

Asked about the bill's chances, a spokesman for Lofgren said the congresswoman thinks Poe would be best suited to address that question. Poe's office did not respond to requests for comment.