Sanctuary policies reduce deportations without increasing crime.

The US government maintains that local sanctuary policies prevent deportations of violent criminals and increase crime. This report tests those claims by combining Immigration and Customs Enforcement (ICE) deportation data and Federal Bureau of Investigation (FBI) crime data with data on the implementation dates of sanctuary policies between 2010 and 2015. Sanctuary policies reduced deportations of people who were fingerprinted by states or counties by about one-third.