Montana has done something that many states and the United States Congress have debated but failed to do: it has just enacted the first attempt to close the dreaded, invasive, unconstitutional, but easily fixed “data broker loophole.” This is a very good step in the right direction because right now, across the country, law enforcement routinely purchases information on individuals it would otherwise need a warrant to obtain. What does that mean? In every state other than Montana, if police want...