A New York judge granted two chimpanzees a writ of habeas corpus on Monday.

In other words, the chimps have the right to a day in court – under a law that only applies to people.

A judge’s ruling is “a big step” toward “the right to bodily liberty for chimpanzees and other cognitively complex animals,” says the head of the Nonhuman Rights Project.

This isn’t coming from nowhere: The Nonhuman Rights Project has been trying to get chimps the rights of personhood for years. They represent the animals in court, arguing that their living situations – as pets or performers – should be considered as unlawful as the inhumane detention of a human.

Previous cases in the United States have failed to produce such a result, but in December an Argentinian orangutan won her case (which was of course actually brought to the court by animal rights activists) and was moved from a zoo to a sanctuary.

The U.S. case isn’t quite at that point yet: The judge hasn’t ruled that the two chimps, who live in a Stony Brook University lab, need to be released. The decision really only means that the chimps have the right to fight their detention in court. It’s entirely possible that the judge will hear all sides of the case and rule that Stony Brook researchers have every right to keep using the chimps in their lab.

While it’s a little soon to start throwing open the doors of every zoo in the country, NhRP representatives are thrilled.

“This is a big step forward to getting what we are ultimately seeking: the right to bodily liberty for chimpanzees and other cognitively complex animals,” Natalie Prosin, the executive director of the NhRP, told Science Magazine. “We got our foot in the door. And no matter what happens, that door can never be completely shut again.”

NhRP has made no secret of its long-term plans to seek out basic human rights for intelligent animals, such as dolphins, whales, elephants, and great apes. While it’s unlikely that judges will grant these two chimps the rights of full personhood, the progress of their case will almost certainly lead to even more lawsuits against zoos, research facilities, and private chimp owners.