“These aren’t questions to be resolved by free-for-alls on cable news channels. They require facts and analysis. And yet, although the United States shells out well over $100 billion each year for public safety, we have remarkably little idea whether that money is well spent. It’s possible that any given policing tactic or technology — from Tasers to facial-recognition systems to body cameras — is a fine or poor idea. But we really don’t have much sense of which tactics and tools work, or whether they are worth the cost. We don’t know how much money we may be wasting, or whether we are compromising civil liberties, or harming people or property, without good reason.”