Habeas corpus, or the Great Writ, is the legal procedure that keeps the government from holding you indefinitely without showing cause. When you challenge your detention by filing a habeas corpus petition, the executive branch must explain to a neutral judge its justification for holding you. Habeas corpus prevents the King from simply locking up subjects in secret dungeons and throwing away the key. It’s been a pillar of Western law since the signing of the Magna Carta in England in 1215. 
 
 The Founders of our nation believed habeas corpus was so essential to preserving liberty, justice, and democracy that they enshrined it in the very first article of the United States Constitution. 
 
 What happened to habeas corpus? 
 
 In its waning days, the last Congress passed the Military Commissions Act (MCA) of 2006. Among many ill-considered and dangerous provisions, the MCA revoked the right to habeas corpus for anyone detained at Guantánamo Bay as well as for any foreigner the government detains anywhere and labels an “enemy combatant.” This provision applies to legal residents of the U.S. as well, meaning someone who has lived in the U.S. for years could potentially be labeled an “enemy combatant” and then thrown into prison with no legal recourse to challenge their detention. 
 
 How does it relate to Guantanamo? 
 
 The government has little or no evidence against most of the men detained at Guantánamo. We now know that almost none of the Guantánamo prisoners were taken into custody by U.S. forces or captured on any battlefield. The overwhelming majority were sold into captivity by Northern Alliance and Pakistani warlords for substantial bounties—$5,000 and more for each person they turned in; enough money, as leaflets the U.S. military distributed throughout Afghanistan said, “to take care of your family . . . for the rest of your life.” In fact, of the nearly 800 men that have been held at Guantánamo, only 10 have ever been charged with any crime. 
 
 Soon after the first 20 detainees were flown to Guantánamo, CCR began filing habeas corpus petitions asking the government to explain why it was holding these men outside of the reach of the U.S. court system in what has since become a notorious offshore penal colony. Despite numerous legal victories that affirm the detainees’ right to challenge their detention, the Bush administration has managed to prevent the detainees from getting a fair hearing in the courts. 
 
 What does it mean for the detainees? 
 
 In June 2007, the Supreme Court decided to hear CCR’s most recent case challenging the detention of many Guantanamo detainees. These men have faced indefinite detention, sham trials, and conditions rapidly inducing psychological deterioration for nearly six years. In the coming Supreme Court term, for the third time, the high court will hear the detainees’ cases and, we hope, once more seek to hold the Administration accountable and uphold habeas corpus. 
 
 The MCA extends a second-class system of justice far beyond Guantánamo to any non-citizen – including legal permanent residents of the U.S. – anywhere in the world whom the executive unilaterally declares to be an “unlawful enemy combatant.” 
 
 What does it mean for everyone else? 
 
 Habeas corpus was originally meant to act as a bulwark precisely against this type of executive power. The founders of our nation considered habeas corpus the most fundamental of rights because it insured that the executive branch could not hold people without cause. Since the founding of the U.S., the writ has been suspended on only four occasions, each for a brief period of time and each in territory that was an active combat zone. 
 
 By compromising this core legal value and necessary protection against the executive branch, the MCA has eroded the very foundation of our legal and constitutional framework. If we do not defend the right to habeas corpus, we all lose. ||||| Update, 21 April: Science has learned that the court order referred to in this story has been amended. The words “writ of habeas corpus” have been struck out, suggesting that the court has made no decision on whether Hercules and Leo—two research chimpanzees at Stony Brook University in New York—deserve to be treated as legal persons. The Nonhuman Rights Project has responded to the amendment, stating, “This case is one of a trio of cases that the Nonhuman Rights Project has brought in an attempt to free chimpanzees imprisoned within the State of New York through an ‘Article 70-Habeas Corpus’ proceeding. These cases are novel and this is the first time that an Order to Show Cause has issued. We are grateful for an opportunity to litigate the issue of the freedom of the chimpanzees, Hercules and Leo, at the ordered May hearing.” Stony Brook has also issued a statement about the case: “The University does not comment on the specifics of litigation, and awaits the court's full consideration on this matter.” 
 
 Update, 22 April: The court hearing has been moved back from 6 May to 27 May. At that time, the judge will hear legal arguments regarding whether Hercules and Leo should remain at Stony Brook. 
 
 In a decision that seems to recognize chimpanzees as legal persons for the first time, a New York judge today granted a pair of Stony Brook University lab animals the right to have their day in court. The ruling marks the first time in U.S. history that an animal has been covered by a writ of habeas corpus, which typically allows human prisoners to challenge their detention. The judicial action could force the university, which is believed to be holding the chimps, to release the primates, and could sway additional judges to do the same with other research animals. 
 
 “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,” says Natalie Prosin, the executive director of the animal rights organization, the Nonhuman Rights Project (NhRP), that filed the case. “We got our foot in the door. And no matter what happens, that door can never be completely shut again.” 
 
 Richard Cupp, a law professor at Pepperdine University in Malibu, California, and a noted opponent of personhood for animals, cautions against reading too much into the ruling, however. “The judge may merely want more information to make a decision on the legal personhood claim, and may have ordered a hearing simply as a vehicle for hearing out both parties in more depth,” he writes in an e-mail to Science. “It would be quite surprising if the judge intended to make a momentous substantive finding that chimpanzees are legal persons if the judge has not yet heard the other side’s arguments.” 
 
 The case began as a salvo of lawsuits filed by NhRP in December 2013. The group claimed that four New York chimpanzees—Hercules and Leo at Stony Brook, and two others on private property—were too cognitively and emotionally complex to be held in captivity and should be relocated to an established chimpanzee sanctuary. NhRP petitioned three lower court judges with a writ of habeas corpus, which is traditionally used to prevent people from being unlawfully imprisoned. By granting the writ, the judges would have implicitly acknowledged that chimpanzees were legal people, too—a first step in freeing them. 
 
 The judges quickly struck down each case, however, and NhRP has been appealing ever since. Today’s decision is the group’s first major victory. In her ruling, New York Supreme Court Justice Barbara Jaffe orders a representative of Stony Brook University to appear in court on 6 May to respond to NhRP’s petition that Hercules and Leo “are being unlawfully detained” and should be immediately moved to a chimp sanctuary in Florida. Both animals have been used to understand the evolution of human bipedalism. (Stony Brook did not immediately respond to a request for comment.) 
 
 Prosin says that even if NhRP loses the case, it will use the habeas corpus ruling to sway judges in other jurisdictions. “It strengthens our argument that these nonhuman animals are not property,” she says. The group plans to file another case—this one involving a captive elephant—by the end of the year and has set its sights on other animals, including research animals, across the country. “We have the scientific evidence to prove in a court of law that elephants, great apes, and whales and dolphins are autonomous beings and deserve the right to bodily liberty,” she says. 
 
 Related content:
– The writ of habeas corpus lets prisoners appear in court to make their captors justify why they're being held. Until now in the US, those who've used this legal tactic have been human. But a New York judge yesterday ruled that the writ may be used by two lab chimpanzees at Stony Brook University, Science magazine reports. NY Supreme Court Justice Barbara Jaffe ordered a university rep to address a suit filed by the Nonhuman Rights Project by appearing in court May 6 to argue why the college is holding Hercules and Leo. The group, which says the animals are being detained for biomedical experiments, says its ultimate goal is to have the animals released to the Save the Chimps sanctuary in Fort Pierce, Fla., per the NhRP's website. "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 project's executive director, tells Science. The case kicked off in December 2013 with lawsuits that also included two chimps held on private property; each case was struck down, sending the NhRP down the appeals path. Not everyone's convinced the upcoming hearing will mean liberation for the chimps. A Pepperdine University law professor tells Science that the judge likely just wants to hear both sides of the story: "It would be quite surprising if the judge intended to make a momentous substantive finding that chimpanzees are legal persons" without doing so, he notes. Prosin, meanwhile, says her group isn't stopping with the chimps and will also target the release of other animals. (Click to read about what chimps talk to each other about.)