(FILES) US President Barack Obama presents the Presidential Medal of Freedom to rights activist Dolores Huerta during a ceremony on May 29, 2012 in the East Room of the White House in Washington. The award is the country's highest civilian honor. AFP PHOTO/Mandel NGAN. US labor leader and civil rights campaigner Dolores Huerta, whose union work with Cesar Chavez changed the lives of migrant workers, has died, her family said. She was 96. Huerta was vice president of United Farm Workers, the union she founded with Chavez, for four decades. (Photo by Mandel NGAN / AFP via Getty Images)