WASHINGTON (AP) — Labor is roaring again, like in the old days. But it's a wounded sound now.

In the bitter aftermath of a showdown with Wisconsin's governor, and as other states move to weaken public employee bargaining rights, unions and their allies dare to hope they can turn rage into revival. This could be a make-or-break moment for a movement that brought the nation the 40-hour week, overtime pay, upward mobility, a storied century of brawls, progressivism and corruption – and now a struggle to stay relevant in the modern age.

One way or another, the Wisconsin Waterloo and the forces it set loose will fill a chapter in organized labor's history. The dispute mobilized masses, attracted public support on the side of workers and set up a political donnybrook to play out in the months ahead as labor leaders seek voters' vengeance against the Republicans who eviscerated union rights.

But it was, at the core, a defeat for labor in the one place where it has stayed strong: the public sector.

Since the heyday of organized labor's influence in the 1950s, when union membership reached its peak at about one of every three workers, unions have fought a losing battle against the steady erosion of membership and clout.

Last year, union membership fell to 11.9 percent of all workers and just 6.9 percent of the private sector. The number of major strikes in 2009 and 2010 was the lowest on record.

If you're a labor sympathizer wondering why unions got weak, pick your poison.

The decline of unions in the private sector mirrored the push to globalization, especially the loss of U.S. manufacturing jobs to other countries and the shift of other factories from the long-time industrial heartland to states less hospitable to organized labor.
Companies took an increasingly aggressive stance against union organizers, emboldened by the Reagan administration's firing of 11,000 striking air traffic controllers in 1981. That action was taken as a wink to the corporate world that the long-established order was upended and that business, too, could play rough.

In the mid-1970s, when miners pulled off one of their multiple massive strikes, they choked coal production, idled steel plants that were starved of fuel and caused rolling brownouts in New York City. Americans far removed from strikes sharply felt their effects.

Not now.

In the 1970s, the nation saw an average of 269 major strikes or lockouts each year. The number has dropped precipitously ever since, to 17 per year over the past decade. The five in 2009 were the fewest since the Bureau of Labor Statistics started counting in 1947.

When industrial unions negotiated higher wages and better working conditions in more influential times, those advances rippled through the economy, setting a benchmark for union and non-union workplaces. With less than seven percent of the private sector unionized now, contracts no longer have the reach to raise all boats.

Young workers today float from job to job and often have little vested interest in long-term improvements in employee satisfaction at a company. That has made it harder to organize new generations to replace the loyalists of old.

To be sure, unions have made recent strides in pulling in new members in the service sector and health care industry. Labor remains a powerful political force. Senate Majority Leader Harry Reid, D-Nev., owes his narrow re-election victory last year to the dogged work of union organizers.

“There is no institution in America on either side of the aisle that has an infrastructure that gets people to the polls like the labor movement,” said Amy Dean, a former head of the AFL-CIO in California's Silicon Valley. “Nobody can put people out on the streets and go door-to-door like we can.”

Public sector unions have grown in recent decades as labor leaders found less resistance in state legislatures – the first being Wisconsin in 1959 – to granting public employees collective bargaining rights. In 2009, for the first time ever, there were more union members working for federal, state, local and municipal governments than in all of the private sector.

Now that trend is meeting the budget crunch in state after state and running into waves of Republicans elected in November. Conservatives see this as an opportunity to show that public-sector unions simply spend dues to elect Democratic lawmakers with the goal of boosting government workers' wages and benefits, even if it means raising taxes for everyone else to pay for it.

Now union leaders and Democrats are pinning their hopes on a backlash that will spread into next year's elections and help fuel recall efforts to oust GOP lawmakers who backed the anti-union agenda.