Here's an excerpt from a Wall Street Journal article about farm labor and the UFW's "Take Our Jobs" Campaign:

In a summer campaign, the United Farm Workers of America is challenging unemployed Americans to harvest the grape, peach and lettuce crops.

Expectations are low. The union's campaign, called "Take Our Jobs," is intended to highlight the role of illegal workers in feeding Americans and to goad Congress to overhaul U.S. immigration policy.

"I can't imagine we'll find that many Americans want to work in the fields," said Arturo Rodriguez, president of the California-based union.

Immigration has reemerged as a prominent national issue since Arizona passed a controversial law to crack down on illegal immigrants that is set to take effect July 29. This week, the Obama administration filed a lawsuit to block it, heightening the political stakes on immigration for both parties ahead of November elections.

About 1.8 million people work on U.S. farms. About three-quarters of them are foreign-born and more than half are illegal immigrants, according to the Department of Labor. The union says the proportion of undocumented workers in the fields is even higher.

But kicking them out, the union argues, would lead to crops rotting in the fields, higher food prices and a greater reliance on imports.

"If we asked all the undocumented immigrants to leave the country, the agriculture industry would die," Mr. Rodriguez said.