The American Civil Liberties Union and Supreme Court Justice Antonin Scalia don’t often agree, but the increasingly widespread practice of collecting DNA from arrested individuals is bringing progressives and conservatives together in opposition. Our DNA is our most intimate personal information, and government should not have the right to seize it and store it in a permanent database merely because a person is suspected of having committed a crime.

All 50 states and the federal government collect DNA samples from convicted felons, but in recent years, many states have expanded this program to allow police to collect DNA from anyone arrested for any offense — even if the detainee is never charged with a crime, much less convicted. This DNA is entered into state-level databases and uploaded to the FBI’s international database, where it is kept permanently.

However reasonable it may be to store the genetic information of convicted criminals, expanding collection to include all those arrested runs counter to the founding principles of our country’s system of justice. “Innocent until proven guilty” isn’t just a cliche, it’s a check on the forces of tyranny. When police arrest an individual, that person is merely under suspicion of a crime, and our justice system ought to view him or her as no more a criminal than you or I until they have been convicted by a jury of their peers. Instead, states from California to Texas to Maryland are forcibly extracting DNA from detainees as soon as police decide to make an arrest, even though the majority are released without being charged with a crime.

There’s a line between reasonable crime prevention measures and violations of our civil liberties, and this crosses it. As Justice Scalia argued in a dissenting opinion after the Supreme Court upheld Maryland’s DNA collection law, the Fourth Amendment forbids unwarranted and unreasonable searches and seizures of this type. While it’s hardly surprising to see the high court’s most stalwart conservative oppose government intrusion into personal matters, it’s rare that leading conservatives find themselves on the side of the ACLU, which has taken the lead in opposing DNA collection laws.

States like to argue that the more data the government has, the more criminals the police will be able to put away. But mass collection of DNA hasn’t led to a significant number of cases solved — in fact, of the 33,000 samples taken by Maryland police, only 13 led to a conviction. In other words, 99.96 percent of detained Marylanders who had their most personal biological information entered into a state and federal database without their consent were never convicted of any crime, and many were never even charged.

Supporters of forced DNA collection may linger on the small number of cases solved through this technology, and argue that the state has the responsibility to do anything within its power to prevent crime. But by this logic, we may as well authorize the government to swab kindergarteners for DNA, mandate recording devices in cellphones, and install cameras in every home.

In an authoritarian state, governments take extreme measures to track control their population, and although harvesting and storing genetic material from suspected criminals may not seem like a harsh measure, it sets us on a slippery slope away from limited government, civil liberties, and respect for the rights of individuals.

Jason Stverak is President of the Franklin Center for Government and Public Integrity