For thousands of South Florida's illegal immigrants, the new year offers more uncertainty, discontent and, for many, resigned departure. From farms in Homestead to day laborer pickup sites in Florida City and Fort Lauderdale, migrant workers are struggling to find work as Homeland Security steps up enforcement after a firestorm of public opinion derailed an immigration overhaul in Congress. That proposal, which failed in the summer, would have eventually legalized millions of undocumented workers. Adding to the turmoil: a slowing economy. More than two dozen South Florida employers and undocumented workers interviewed by The Miami Herald and El Nuevo Herald...