When Immigration and Customs Enforcement (ICE) agents raided a New Bedford, Mass., factory in March, they arrested 361 alleged illegal aliens and their bosses. Owner Francesco Insolia and two managers face up to 10 years in prison and $250,000 fines for conspiring to harbor illegal aliens, as well as six months in prison and $10,000 fines for each illegal worker hired.

The raid at Michael Bianco Inc. was one of dozens in ICE's stepped-up work-site enforcement program. The number of workers detained in raids soared from 848 in 2004 to almost 4,000 in just the first half of 2007.

ICE also raised the stakes for employers by focusing on filing criminal charges against executives and managers who hire illegals.

“It's what I call enforcement by propaganda,” says Richard Whitlock, partner in Fisher & Phillips. “They are targeting the biggest fish and throwing the book at them because that scares everyone else.”

The only bright spot came in October when a federal judge issued a permanent injunction against a Department of Homeland Security plan to use Social Security mismatch letters as an enforcement tool.