By STEVEN GREENHOUSE

In demonstrations and marches in 70 cities, the labor movement seized on International Human Rights Day yesterday to begin a campaign asserting that American corporations routinely violate an internationally guaranteed right: the right to unionize.

THE WORLD'S SWEATSHOP: THE ETCH A SKETCH CONNECTION

By JOSEPH KAHN

SHENZHEN, China — Workers at Kin Ki Industrial, a leading Chinese toy maker, make a decent salary, rarely work nights or weekends and often "hang out along the street, play Ping-Pong and watch TV."

They all have work contracts, pensions and medical benefits. The factory canteen offers tasty food. The dormitories are comfortable.

The 70,000 grocery workers on strike in Southern California are the front line in a battle to prevent middle-class service jobs from turning into poverty-level ones. The supermarkets say they are forced to lower their labor costs to compete with Wal-Mart, a nonunion, low-wage employer aggressively moving into the grocery business. Everyone should be concerned about this fight. It is, at bottom, about the ability of retail workers to earn wages that keep their families out of poverty.

By Kevin Sullivan and Mary Jordan

ECATEPEC, Mexico -- Jesus Santana Hernandez opened his refrigerator and looked at the contents: a bottle of water and an onion. His mother was at work washing dishes in a taco joint. So it fell to Jesus, a wiry 12-year-old, to feed his three younger brothers and sisters. The onion was no help. He grabbed the water.