PAGE ONE advertisement Crucial Ingredient As Border Tightens, Growers See Threat to 'Winter Salad Bowl' Yuma, Ariz., Relies on Muscle From Illegal Immigrants; Security vs. Economics A Job Americans Won't Do By MIRIAM JORDAN Staff Reporter of THE WALL STREET JOURNAL March 11, 2005; Page A1 YUMA, Ariz. -- Shortly before Thanksgiving last year, Tom Nassif did something few law-abiding citizens would ever think to do: He called the U.S. Border Patrol here and suggested agents stop manning a highway checkpoint intended to keep illegal immigrants out of the country. A former U.S. ambassador and currently the president of a...