U.S. union membership has been in a steep decline over the past 40 years – so have strikes and lockouts.

There were five – count ‘em, five – strikes or lockouts of significance in the U.S. in 2009. That was the lowest number since the Bureau of Labor Statistics started keeping track in 1947. That number “spiked” to 11 in 2010 and 19 in 2011. The numbers for 2012 come out this month.

Compare that to 40 years ago, when there were an average of 289 major work stoppages a year. By the 1990s, that had fallen to about 35 per year. A major work stoppage, according to the BLS, involves 1,000 or more workers.

“The strike has almost disappeared from American life,” wrote Chris Rhomberg, an associate professor of Sociology for Fordham University, a for a CNN article. Judicial philosophies and politics have turned against unions. “We have essentially gone back to a pre-New Deal era of workplace governance.”

“Before the 1930s,” Rhomberg continued, “American unions confronted a legal environment that historians have described as ‘judicial repression.’ During that time, federal courts repeatedly struck down workers’ rights to organize and act collectively, making unions themselves all but illegal.

“In 1935, the National Labor Relations Act created a process for legally recognizing union representation and managing private-sector labor conflict. The result was historic democratization of the American workplace and economy. The strike was a crucial part of this system: While the law was intended to reduce industrial strife, it also relied on the right to strike to protect the integrity of the bargaining process.”

With weaker unions, that ability to effectively strike – and raise workers’ living standards – has been diminished.