In the written decision and during oral arguments, the majority made clear they did not intend to abolish all workplace rights for illegal immigrants. However, dissenters on the court, along with labor unions, immigrant-rights groups and a coalition of business groups that filed briefs on behalf of the worker, argued that such a ruling would increase exploitation by unscrupulous employers.

Some say that already has happened.

"It's amazing, the quickness of the employer response to this," said Ana Avendano Denier, an attorney with the United Food and Commercial Workers Union, which represents thousands of immigrant workers in meat and poultry plants. "Some are intentionally reading it too broadly, but there's also a lot of misunderstanding about what the court said."

In recent weeks, she said, a worker filing a sexual harassment complaint at a Kentucky poultry plant was allegedly asked for her immigration documents, as was a meatpacking worker in Nebraska who filed a workers' compensation claim after a 30-foot fall. Because both cases are being handled through the union grievance process, Denier said she could not supply the names of the employers.

In New York, the owner of a Manhattan meat market who is accused of paying his immigrant work force less than the minimum wage warned an advocacy group not to demonstrate in front of his store.

"I am sure you are aware of the ruling by the Supreme Court of the United States that illegal immigrants do not have the same rights as U.S. citizens," the owner's attorney, Frederick Margolin, told the group in a letter.

In an interview last week, Margolin said he believed that a worker fired from the market was not entitled to the difference between his wages over five years and the minimum wage because "that's back pay." He added that the employer probably knew the worker was undocumented because "that's true of maybe 75% of the employees in the area."  [ Continue.........