Supporters of tougher immigration enforcement are criticizing Cook County Sheriff Tom Dart for seeking legal options enabling the county’s massive jail to quit holding some inmates wanted for immigration violations.

Dart told WBEZ last week his department was looking for a way to end its blanket compliance with Immigration and Customs Enforcement requests that detainees be held 48 hours beyond what their local criminal cases require. The holds, financed by the county, help ICE take custody and begin deportation proceedings. Dart says the jail’s role erodes community trust in local law enforcement, discouraging witnesses and even victims from cooperating with police.

Ira Mehlman, spokesman of a Washington-based pro-enforcement group called the Federation for American Immigration Reform, is not convinced. “This idea that turning people over to immigration authorities — who have already been picked up on suspicion of some crime — is somehow going to cause this massive chill just doesn’t hold water,” says Mehlman, who accuses Dart of “putting politics ahead of community safety.”

The WBEZ report has also led to a torrent of comments on the station’s Web site. The visitors have labeled Dart everything from a “fool” to a “traitor.”

But Dart’s review is also winning praise. “Sheriffs throughout the country are revisiting their policies with respect to the ICE holds,” says Fred Tsao, policy director of the Illinois Coalition for Immigrant and Refugee Rights. “The criminal justice system already distinguishes between people who can be released with no threat to public safety and those who cannot.”

San Francisco County Sheriff Michael Hennessey on June 1 quit honoring ICE requests for holds of inmates arrested for certain traffic infractions and other low-level offenses if a background check finds no felony convictions and meets other requirements. Since then, his department has released four inmates with ICE detainers, according to Eileen Hirst, the sheriff’s chief of staff.

ICE officials acknowledge that local jails have no legal requirement to comply with the detainer requests.