State and local authorities from New Hampshire to San Francisco have begun banning the use of facial-recognition technology. Their suspicion is well founded: these algorithms make lots of mistakes, particularly when it comes to identifying women and people of color. Even if the tech gets more accurate, facial recognition will unleash an invasion of privacy that could make anonymity impossible. Unfortunately, bans on its use by local governments have done little to curb adoption by businesses from start-ups to large corporations. That expanding reach is why this technology requires federal regulations—and it needs them now.