Immigration inspectors who pored over the records of one of those growers, Gebbers Farms, found evidence that more than 500 of its workers, mostly immigrants from Mexico, were in the country illegally. In December, Gebbers Farms, based in this Washington orchard town, fired the workers.

“Instead of hundreds of agents going after one company, now one agent can go after hundreds of companies,” said Mark K. Reed, president of Border Management Strategies, a consulting firm in Tucson that advises companies across the country on immigration law. “And there is no drama, no trauma, no families being torn apart, no handcuffs.”

President Obama, in a speech last week, explained a two-step immigration policy. He promised tough enforcement against illegal immigration, in workplaces and at the border, saying it would prepare the way for a legislative overhaul to give legal status to millions of illegal immigrants already in the country. White House officials say the enforcement is under way, but they acknowledge the overhaul is unlikely to happen this year.

In another shift, the immigration agency has moved away from bringing criminal charges against immigrant workers who lack legal status but have otherwise clean records.

Republican lawmakers say Mr. Obama is talking tough, but in practice is lightening up.

“Even if discovered, illegal aliens are allowed to walk free and seek employment elsewhere” said Senator Jeff Sessions of Alabama, the senior Republican on the Judiciary Committee. “This lax approach is particularly troubling,” he said, “at a time when so many American citizens are struggling to find jobs.”