From 2010 until last spring, the Virginia State Police (VSP) maintained a massive database of license plates that allowed them to pinpoint the locations of millions of cars on particular dates and times. Even more disturbing, the agency used automatic license plate readers (ALPRs) to collect information about political activities of law-abiding people. The VSP recorded the license plates of vehicles attending President Obama’s 2009 inauguration, as well as campaign rallies for Obama and vice presidential candidate Sarah Palin. (Documentation of this program, disclosed in response to an ACLU of Virginia public records request, can be found here.) These practices starkly illustrate the need for tight controls on government use of technology for surveillance purposes.