Is labor losing its voice? Once a major force in the nation's economy and politics, unions have fallen on hard times. Can they convince a new generation of workers that they're still relevant?

• Author: Greenhouse, Steven
• Position: Cover Story

When he was a high school senior a few years ago, Josh Noble took a part-time job changing tires and installing batteries at a Wal-Mart tire-and-lube garage in his hometown of Loveland, Colo., north of Denver.

Noble liked working on cars, but after two years at Wal-Mart, several things bothered him: The company paid him less than local supermarkets would have, its health plan was expensive, and the garage paid some new workers more than it paid him. "I was fed up," Noble says, complaining that he earned so little that he had to give up his apartment and move back in with his parents.

So Noble did what dissatisfied workers have done for decades to try to improve their wages and working conditions: He attempted to form a labor union. In seeking to unionize the garage's 18 workers, Noble created a huge fuss. Here was a snowboard-loving, earring-wearing 21-year-old taking on Wal-Mart, the world's largest corporation, with 1.7 million workers worldwide. If Noble prevailed, he would create the first successful union at any of the nation's 3,650 Wal-Mart stores.

POWERHOUSE PAST

Many union leaders embraced Noble's cause, seeing young people like him as the best hope for America's problem-plagued labor movement. Fifty years ago, organized labor was a powerhouse, representing about 35 percent of the U.S. workforce, able to pressure even the largest corporations to grant generous contracts that helped America build the world's biggest middle class.

After becoming a political force in the 1930s, unions successfully pushed Congress to enact the minimum wage and the 40-hour workweek. During World War II and in the decade after, they played a pivotal role in securing medical coverage and pensions for millions of union and nonunion workers alike. And in the 1970s, they helped win passage of the Occupational Safety and Health Act (OSHA), which sets safety standards for the nation's workplaces.

Just how influential were America's unions? In 1961, the hatters union, alarmed that fewer men were wearing hats, persuaded John F. Kennedy to wear a top hat at his presidential inauguration.

Today, however, labor unions are struggling and now represent just 12.5 percent of the nation's workers. As manufacturing, labor's longtime stronghold, continues to shrink in the U.S., unions are groping for ways to reverse their decline. Their strategies include trying to attract more young workers, immigrants, and low-wage workers, many in service industries.

"Unions can still...