The fastest growing population in federal custody is immigrant detainees.

Enforcement programs such as Operation Streamline, under the Department of Homeland Security (DHS), have contributed to this growth. The Warren Institute found that Operation Streamline targets immigrant workers with no criminal history and routes them into criminal prosecution and imprisonment instead of the civil immigration system.

In federal prisons, the proportion of non citizens has increased steadily, as a Pew Hispanic Center study found. Non citizen offenders rose from almost 23 percent in 1991 to more than 37 percent, according to recent data. Hispanics account for more than 80 percent of non citizen offenders.

When it comes to detention and confinement, private corporations and local jailers are focused on what researchers Judy Greene and Sunita Patel call "the immigrant goldrush" – a race to house immigrant detainees.

Since 2003, U.S. Immigration and Customs Enforcement (ICE), which falls under DHS, has expanded the number of beds for immigrant detainees. The Corrections Corporation of America (CCA), GEO Groups and other companies invested in building prisons have benefited from federal detention contracts. Local jailers reportedly have been able to close budget gaps from these contracts.

The impulse to view detention and imprisonment as merely a response to more undocumented immigrants committing crimes is off mark. In federal prisons, for example, the bulk of undocumented immigrants being sentenced – a full 75 percent – are there because of illegal entry or status in the country, not hard crimes. While immigration prosecutions are projected to increase by 14 percent, prosecutions for white-collar crimes, drugs and weapons show a downward trend, reports the Warren Institute.

ICE says that it is focusing on people who may pose risks to public safety. Under the current administration, the agency is working on implementing a host of welcomed changes to address some issues with immigration detention. But the deep flaws with the U.S. immigration system, the racial profiling that happens locally and the absence of fundamental reform all affect detention. And when immigrants are unnecessarily detained, as with the case of Jean Montrevil in New York recently, it does little to boost the confidence of the public.

What also remains troublesome is how private corporations view immigrant detention as a cash cow. This, along with how detainee bed space for years has received millions of more dollars in funding than alternatives to detention, is cause for vigilance.

Private prison corporations build facilities in anticipation of detainees and inmates. CCA bills prisons as economic stimulus for towns. The corporation has spent significant money lobbying legislators who sit on appropriations committees.

The branding of immigrants as criminals by the anti immigrant lobby has served the business of detention well. When an agenda aims to dehumanize a people in the public imagination, it becomes easy to win support policies that corral, separate and punish them.

Even with some changes underway, the criminal justice reform movement, elected leaders and citizens must act. In recent years, crime rates have dropped in many cities and policy shifts around federal sentencing have been introduced, for example. But this long-fought-for progress stands to be undercut by a pipeline of immigrants to imprisonment.