For those that say this is impossible, take a look at these slides from Dstillery, a major demand side advertising company: https://www.matroid.com/scaledml/2017/claudia.pdf Pay particular attention to slide #23, and also the following few slides, which shows the architecture of their data processing stack. They are deanonymizing most of what people do on the web, and they undoubtedly have a file on most all members of Congress. Part of the input to this model is the "anonymized" location data that mobile phone companies sell. If you already know where a person lives and works though, or simply have a few retail transactions with timestamps, you can deanonymize these location traces.