As of September 2014, Iowa county jails had told the ACLU of Iowa that they have decided against holding people at the request of Immigration and Customs Enforcement (ICE) simply because the individuals are suspected of not having proper immigration authorization. Local law enforcement made that decision because of growing awareness about the unconstitutionality of the detainers. Click here for details.
However, the Iowa Legislature since passed legislation, SF481, that requires law enforcement in Iowa to "comply with" ICE detainers in many circumstances—even though detainers are "voluntary" by their own terms. We believe this law is unconstitutional. Read more here.
More than 200 local jurisdictions nationwide have stopped holding people on ICE detainers entirely.
For an example, in Buquer v. City of Indianapolis, the court stated “A detainer is not a criminal warrant, but rather a voluntary request….”