Immigrants are the fastest-growing sector of the U.S. prison population. The DHS agency Immigration and Customs Enforcement (ICE) detains 300,000 immigrants annually, with some 32,000 immigrants in ICE detention centers on any given day. ICE's budget for its Detention and Removal Operations has jumped from $959 million in 2004 to $2.3 billion today.

The rise in the number of immigrants detained or incarcerated by the federal government for immigration-related offenses dates back to the mid-1990s when Congress passed the Anti-Terrorism and Effective Death Penalty Act and the Immigration Reform and Immigrant Responsibility Act. ....